Error passing Session Variable to SQLDataSource

I'm trying to run Project.aspx. Admin.apsx, when the 'VIEW PROFILE' button is clicked, is supposed to create a session "project_id" so the two SQLDataSources get the project_id values from the Session("project_id").

I'm getting this error:

Project.aspx

<%@ Page Title="" Language="VB" MasterPageFile="~/MasterPage.master" AutoEventWireup="false" CodeFile="Project.aspx.vb" Inherits="Project" %>


<%@ Register assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" namespace="System.Web.UI.DataVisualization.Charting" tagprefix="asp" %>



<asp:Content ID="Content3" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <div id="project-image"><asp:Image ID="Image1" runat="server" Height="124px" Width="93px" />
        <asp:FormView ID="frmViewProject" runat="server" DataKeyNames="project_id" DataSourceID="SqlDataSource1" HorizontalAlign="Justify">
            <EditItemTemplate>
                project_id:
                <asp:Label ID="project_idLabel1" runat="server" Text='<%# Eval("project_id") %>' />
                <br />
                project_type:
                <asp:TextBox ID="project_typeTextBox" runat="server" Text='<%# Bind("project_type") %>' />
                <br />
                project_start:
                <asp:TextBox ID="project_startTextBox" runat="server" Text='<%# Bind("project_start") %>' />
                <br />
                project_finish:
                <asp:TextBox ID="project_finishTextBox" runat="server" Text='<%# Bind("project_finish") %>' />
                <br />
                project_duration:
                <asp:TextBox ID="project_durationTextBox" runat="server" Text='<%# Bind("project_duration") %>' />
                <br />
                project_budget:
                <asp:TextBox ID="project_budgetTextBox" runat="server" Text='<%# Bind("project_budget") %>' />
                <br />
                project_cost:
                <asp:TextBox ID="project_costTextBox" runat="server" Text='<%# Bind("project_cost") %>' />
                <br />
                project_name:
                <asp:TextBox ID="project_nameTextBox" runat="server" Text='<%# Bind("project_name") %>' />
                <br />
                <asp:LinkButton ID="UpdateButton" runat="server" CausesValidation="True" CommandName="Update" Text="Update" />
                &nbsp;<asp:LinkButton ID="UpdateCancelButton" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel" />
            </EditItemTemplate>
            <EditRowStyle BorderStyle="Solid" Font-Bold="False" Font-Names="Verdana" Font-Overline="False" Font-Size="Small" HorizontalAlign="Right" VerticalAlign="Middle" />
            <InsertItemTemplate>
                project_type:
                <asp:TextBox ID="project_typeTextBox" runat="server" Text='<%# Bind("project_type") %>' />
                <br />
                project_start:
                <asp:TextBox ID="project_startTextBox" runat="server" Text='<%# Bind("project_start") %>' />
                <br />
                project_finish:
                <asp:TextBox ID="project_finishTextBox" runat="server" Text='<%# Bind("project_finish") %>' />
                <br />
                project_duration:
                <asp:TextBox ID="project_durationTextBox" runat="server" Text='<%# Bind("project_duration") %>' />
                <br />
                project_budget:
                <asp:TextBox ID="project_budgetTextBox" runat="server" Text='<%# Bind("project_budget") %>' />
                <br />
                project_cost:
                <asp:TextBox ID="project_costTextBox" runat="server" Text='<%# Bind("project_cost") %>' />
                <br />
                project_name:
                <asp:TextBox ID="project_nameTextBox" runat="server" Text='<%# Bind("project_name") %>' />
                <br />
                <asp:LinkButton ID="InsertButton" runat="server" CausesValidation="True" CommandName="Insert" Text="Insert" />
                &nbsp;<asp:LinkButton ID="InsertCancelButton" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel" />
            </InsertItemTemplate>
            <InsertRowStyle HorizontalAlign="Center" VerticalAlign="Middle" />
            <ItemTemplate>
                project_id:
                <asp:Label ID="project_idLabel" runat="server" Text='<%# Eval("project_id") %>' />
                <br />
                project_type:
                <asp:Label ID="project_typeLabel" runat="server" Text='<%# Bind("project_type") %>' />
                <br />
                project_start:
                <asp:Label ID="project_startLabel" runat="server" Text='<%# Bind("project_start") %>' />
                <br />
                project_finish:
                <asp:Label ID="project_finishLabel" runat="server" Text='<%# Bind("project_finish") %>' />
                <br />
                project_duration:
                <asp:Label ID="project_durationLabel" runat="server" Text='<%# Bind("project_duration") %>' />
                <br />
                project_budget:
                <asp:Label ID="project_budgetLabel" runat="server" Text='<%# Bind("project_budget") %>' />
                <br />
                project_cost:
                <asp:Label ID="project_costLabel" runat="server" Text='<%# Bind("project_cost") %>' />
                <br />
                project_name:
                <asp:Label ID="project_nameLabel" runat="server" Text='<%# Bind("project_name") %>' />
                <br />

            </ItemTemplate>
            <RowStyle BorderStyle="None" HorizontalAlign="Left" VerticalAlign="Middle" />
        </asp:FormView>
        <asp:Chart ID="chrtComplete" runat="server" DataMember="DefaultView" DataSourceID="SqlDataSource2" EnableViewState="True">
            <series>
                <asp:Series ChartType="Pie" Legend="Completed" Name="Series1" XValueMember="project_start" YValueMembers="project_finish">
                </asp:Series>
            </series>
            <chartareas>
                <asp:ChartArea Name="ChartArea1">
                </asp:ChartArea>
            </chartareas>
            <Legends>
                <asp:Legend LegendStyle="Row" Name="Completed">
                </asp:Legend>
            </Legends>
            <Titles>
                <asp:Title Name="Project Completion">
                </asp:Title>
            </Titles>
        </asp:Chart>
        <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:ConnStringDb1 %>" SelectCommand="SELECT [project_start], [project_finish] FROM [projects] WHERE ([project_id] = @project_id)">
            <SelectParameters>
                <asp:SessionParameter Name="project_id" SessionField="project_id" Type="Int32" />
            </SelectParameters>
        </asp:SqlDataSource>
    </div>
    <div id="project-info">
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnStringDb1 %>" SelectCommand="SELECT [project_id], [project_type], [project_start], [project_finish], [project_duration], [project_budget], [project_cost], [project_name] FROM [projects] WHERE ([project_id] = @project_id)">
            <SelectParameters>
                <asp:SessionParameter Name="project_id" SessionField="project_id" Type="Int32" />
            </SelectParameters>
        </asp:SqlDataSource>
    </div>
&nbsp;
    <br />
</asp:Content>

Admin.aspx

Imports System.Data.SqlClient

Partial Class Admin
    Inherits System.Web.UI.Page

    Protected Sub btnSearchUser_Click(sender As Object, e As EventArgs) Handles btnSearchUser.Click

        Dim conn As New SqlConnection("Data Source=BRIAN-PC\SQLEXPRESS;Initial Catalog=master_db;Integrated Security=True")
        Dim searchComm As String = "SELECT username FROM users WHERE CONTAINS (username, @username)"

        Dim searchSQL As New SqlCommand

        conn.Open()

        searchSQL = New SqlCommand(searchComm, conn)
        searchSQL.Parameters.AddWithValue("@username", txtUserSearch.Text)

        Dim datareader As SqlDataReader = searchSQL.ExecuteReader()

        While datareader.Read

            lstUsers.Items.Add(datareader.Item("username"))

        End While



        datareader.Close()
        conn.Close()

    End Sub

    Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load

    End Sub

    Protected Sub DropDownList1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles drpProjects.SelectedIndexChanged



        Dim conn As New SqlConnection("Data Source=BRIAN-PC\SQLEXPRESS;Initial Catalog=master_db;Integrated Security=True")
        Dim sqlComm As String = "SELECT project_name FROM projects WHERE project_name=@projectname"
        Dim sqlProjname As New SqlCommand

        conn.Open()

        sqlProjname = New SqlCommand(sqlComm, conn)
        sqlProjname.Parameters.AddWithValue("@projectname", drpProjects.SelectedItem.Text)
        Dim datareader As SqlDataReader = sqlProjname.ExecuteReader()
        datareader.Read()


        If datareader.HasRows Then

            lblProjName.Text = datareader("project_name").ToString()
        End If

        datareader.Close()
        conn.Close()

        lblProjName.Visible = True
        grdProjDetails.Visible = True







    End Sub

    Protected Sub btnManageProj_Click(sender As Object, e As EventArgs) Handles btnManageProj.Click

        MultiView1.SetActiveView(View2)


    End Sub

    Protected Sub btnProjSettings_Click(sender As Object, e As EventArgs) Handles btnProjSettings.Click

        Dim conn2 As New SqlConnection("Data Source=BRIAN-PC\SQLEXPRESS;Initial Catalog=master_db;Integrated Security=True")
        Dim sqlComm2 As String = "SELECT project_id FROM projects WHERE project_name=@projectname"
        Dim sqlProjID As New SqlCommand

        conn2.Open()

        sqlProjID = New SqlCommand(sqlComm2, conn2)
        sqlProjID.Parameters.AddWithValue("@projectname", drpProjects.SelectedItem.Text)
        Dim datareader As SqlDataReader = sqlProjID.ExecuteReader()
        datareader.Read()


        If datareader.HasRows Then

            Dim UserID As String
            UserID = datareader("project_id").ToString

            Session("project_id") = UserID
            Server.Transfer("Project.aspx", True)

        End If

        datareader.Close()
        conn2.Close()



    End Sub
End Class

MasterPage.aspx

<%@ Master Language="VB" CodeFile="MasterPage.master.vb" Inherits="MasterPage" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<script runat="server">



    Protected Sub Page_Load(sender As Object, e As EventArgs)

        If Session("userid") = Nothing Then
            txtLoginUser.Visible = True
            txtLoginPass.Visible = True

        Else


            Dim conn As New SqlConnection("Data Source=BRIAN-PC\SQLEXPRESS;Initial Catalog=master_db;Integrated Security=True")
            Dim useridComm As String = "SELECT name, surname FROM users WHERE user_id=@userid"
            Dim sqlUserID As New SqlCommand

            conn.Open()

            Dim userid As String = Session("userid")

            sqlUserID = New SqlCommand(useridComm, conn)
            sqlUserID.Parameters.AddWithValue("@userid", userid)
            Dim datareader As SqlDataReader = sqlUserID.ExecuteReader()
            If datareader.HasRows Then

                FormsAuthentication.RedirectFromLoginPage(datareader("user_id"), True)
                lblLoggedIn.Text = datareader("name").ToString() & " " & datareader("surname").ToString()

            End If
            datareader.Close()
            conn.Close()

        End If
    End Sub

   Protected Sub Button1_Click(sender As Object, e As EventArgs)

        Dim loginSQL As New SqlCommand
        Dim loginComm As String

        Dim CommonFunctions As New CommonFunctions()
        Dim dec_pass As String = CommonFunctions.EncryptPassword(txtLoginPass.Text.Trim)

        Dim conn As New SqlConnection("Data Source=BRIAN-PC\SQLEXPRESS;Initial Catalog=master_db;Integrated Security=True")


        loginComm = "SELECT user_id FROM users WHERE username=@username and password=@password"

        conn.Open()


        loginSQL = New SqlCommand(loginComm, conn)
        loginSQL.Parameters.AddWithValue("@username", txtLoginUser.Text.ToString)
        loginSQL.Parameters.AddWithValue("@password", dec_pass)
        Dim dr As SqlDataReader = loginSQL.ExecuteReader()
        dr.Read()


        If dr.HasRows Then
            Session("userid") = dr("user_id")
        ElseIf dr.HasRows = False Then

            lblRegister.ForeColor = Drawing.Color.Red
            lblRegister.Text = "Incorrect Username/Password."
        End If
        dr.Close()
        conn.Close()

    End Sub





</script>



<head>
    <meta charset="utf-8" />
    <script src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script>
    <title></title>
    <meta name="keywords" content="" />
    <meta name="description" content="" />
    <link rel="stylesheet" href="style.css" type="text/css" media="screen, projection" />
</head>

<body>

    <form id="form1" runat="server">

<div id="wrapper">

    <header id="header">
        <strong>Header:</strong> Mobile CMS

        </header>


<section id="login">

    <div id="login-form">

         <p>

                    <asp:Label ID="lblUsername" runat="server" Font-Bold="True" Text="U:"></asp:Label>
&nbsp;<asp:TextBox ID="txtLoginUser" runat="server" BorderStyle="None" BorderWidth="0px" Wrap="False"></asp:TextBox>
&nbsp;
                    <asp:Label ID="lblUsername0" runat="server" Font-Bold="True" Text="P:"></asp:Label>
                    <asp:TextBox ID="txtLoginPass" runat="server" BorderStyle="None" BorderWidth="0px" TextMode="Password" Wrap="False"></asp:TextBox>
&nbsp;
                    <asp:Button ID="btnLogin" runat="server" BorderStyle="None" OnClick="Button1_Click" Text="Login" />

                </p>

                <p>

                    <asp:Label ID="lblRegister" runat="server" Font-Bold="True" Font-Underline="True" ForeColor="#0000CC" Text="Register"></asp:Label>

                    <asp:Label ID="lblLoggedIn" runat="server"></asp:Label>

                </p>
         <p>

                    &nbsp;</p>



    </div>

</section>

<div class="navigation-bar">
       <ul class="navigation-menu">

            <li><a href="#" class="home">Home</a></li>
            <li><a href="#" class="mainsettings">Settings</a></li>
            <li><a href="#" class="profile">Profile</a>

                <ul>
                    <li><a href="#" class="messages">Messages</a></li>
                    <li><a href="#" class="settings">Profile Settings</a></li>
                </ul>

            </li>
            <li><a href="#" class="uploads">Uploads</a></li>
            <li><a href="#" class="documents">Media</a>


                <ul>
                    <li><a href="#" class="docs">Documents</a></li>
                    <li><a href="#" class="others">Others</a></li>
                </ul>

            </li>

            <li><a href="#" class="projects">Projects</a>


                <ul>
                    <li><a href="#" class="yprojects">Your Projects</a></li>
                    <li><a href="#" class="otherprojects">Other Projects</a></li>
                </ul>

            </li>

        </ul>

    </div>


    <section id="middle">

        <div id="container">
            <div id="content">
                <div>
                    <asp:ContentPlaceHolder id="ContentPlaceHolder1" runat="server">

                    </asp:ContentPlaceHolder>
                </div>
        </div>
        </div>



    </section>

    <footer id="footer">
        <strong>Footer:</strong> adsfdsgfds
    </footer>

</div>

    </form>

</body>
</html>

Screenshot:

What is happening? What is wrong with the code?

I am using VS 2012 Professional with SQL-Server 2012 Express

Code for the 'View Profile' button is in Admin.aspx under btnProjSettings:

  Protected Sub btnProjSettings_Click(sender As Object, e As EventArgs) Handles btnProjSettings.Click

        Dim conn2 As New SqlConnection("Data Source=BRIAN-PC\SQLEXPRESS;Initial Catalog=master_db;Integrated Security=True")
        Dim sqlComm2 As String = "SELECT project_id FROM projects WHERE project_name=@projectname"
        Dim sqlProjID As New SqlCommand

        conn2.Open()

        sqlProjID = New SqlCommand(sqlComm2, conn2)
        sqlProjID.Parameters.AddWithValue("@projectname", drpProjects.SelectedItem.Text)
        Dim datareader As SqlDataReader = sqlProjID.ExecuteReader()
        datareader.Read()


        If datareader.HasRows Then

            Dim UserID As String
            UserID = datareader("project_id").ToString

            Session("project_id") = UserID
            Server.Transfer("Project.aspx", True)

        End If

        datareader.Close()
        conn2.Close()



    End Sub