I'm trying to pass a value stored in a hidden field in a form over to my php script, but can't seem to get it to work.

HTML Code:
<form action='scripts/proc_email_form.php' method='post' name='form' id='form' accept-charset='utf-8'>
       <input type='hidden' name='unreguser' value='4' id='unreguser' />
       <textarea name='message' rows='8'></textarea>

     <input type='submit' value='Send' />
php script
HTML Code:
$unreguser = $_REQUEST['unreguser'];
I have also tried using $_POST