Query string problem if we use header

Hai frnds i am new to php actually i am facing following problems in coding please can anyone give the solution?

1. Actually i am having one audio player and i am displaying some word dcoument
2. if i click word document corresponding audio file should play
3. actually when i click doc file it should pop ip with save as and open with for that i am using some header code
4. also i am passing query string in the browser
5. query string is not working if i use header

can anyone give me a solution for it below is my code i am attaching

<?php

$f_name = $_POST["fn"];
$id = $_POST["id1"];
echo $id;
//echo "../public_html/sites/default/files/ourfiles/$f_name";
$res2=db_query("select * from mt_files where id='".$id."' ");
$row2=db_fetch_array($res2);

$job_audio=$row2["audio_name"];
//echo $job_audio;
//$job_audi=explode("/",$job_audio);
//$job_audio=$job_audi[8];
$job_audio= "C:/xampp/htdocs/med/sites/default/files/audio/$job_audio";
//$job_audio= "C:/Documents and Settings/swuser/My Documents/$job_audio";
//echo $job_audio;


echo "<object data='$job_audio' type='application/x-mplayer2' width='150' height='45'>
<param name='src' value='$job_audio'>
<param name='autoplay' value='true'>
<param name='autoStart' value='1'>

</object> ";


$file = "../mts/sites/default/files/docs/$f_name";

if (file_exists($file)) {
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename='.basename($file));
    header('Content-Transfer-Encoding: binary');
    header('Expires: 0');
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
    header('Pragma: public');
    header('Content-Length: ' . filesize($file));
    ob_clean();
    flush();
    readfile($file);
    exit;
}

//The download table query goes here put the $f_name in insert into with the //time varible


?>