symfony2 custom validator FatalErrorException

I am using Symfony2 and I am trying to build a custom validator for my class.

I followed the guide found Here

I am receiving a weird error:

FatalErrorException: Compile Error: Cannot redeclare class Acme\MyProject\Validator\Constraints\isUniqueNameInPlaces in /home/myfolder/src/Acme/MyProjectBundle/Validator/Constraints/isUniqueNameInPlaces.php line 123

However, file isUniqueNameInPlaces.php is only 14 lines long. I am sure I did something stupid, but I can not find out what. Can someone give me a hand?

Here is my isUniqueNameInPlaces

  <?php

  // src/Acme/MyProject/Validator/Constraints/UniqueNameInPlaces.php
  namespace Acme\MyProject\Validator\Constraints;

  use Symfony\Component\Validator\Constraint;

  /**
  * @Annotation
  */
  class isUniqueNameInPlaces extends Constraint
  {
      public $message = 'Name is not unique';
  }

And here is its validator

  <?php

  // src/Acme/MyProject/Validator/Constraints/isUniqueNameInPlacesValidator.php
  namespace Acme\MyProject\Validator\Constraints;

  use Symfony\Component\Validator\Constraint;
  use Symfony\Component\Validator\ConstraintValidator;

  class isUniqueNameInPlacesValidator extends ConstraintValidator
  {

      public function getTargets()
      {
          return self::CLASS_CONSTRAINT;
      }

      public function validate($protocol, Constraint $constraint)
      {
  //      my logic
      }
  }