Description:
------------
I understand that PHP is server-side and this should really not happen, but I have a purely php page that cannot access the $_SESSION unless a user is using Internet Explorer.  Moreover, Firefox and Opera cannot access it.

Reproduce code:
---------------
<?php require_once('Connections/siteData.php'); ?>
<?php
if (!isset($_SESSION)) {
  session_start();
}
?>
<?php
function storPath($fileType){
	if(stristr($fileType, ".avi") === TRUE || stristr($fileType, ".mov") === TRUE){
		return 'media';
	} else {
		return 'images';
	}	
}
$uploadFile =  $_SESSION['username']."_". basename($_FILES['Filedata']['name'] );
$storage = storPath($uploadFile);
//path name of file for storage
$uploadFilePath = $storage."/".$uploadFile;
//if the file is moved successfully
if ( move_uploaded_file( $_FILES['Filedata']['tmp_name'] , $uploadFilePath ) ) {
	//populate session array to be passed to SQL
	$_SESSION['upFile'][] = $uploadFile;
	echo( '1 ' . $_FILES['Filedata']['name']);
//file failed to move
}else{
	echo( '0');
}
?>

Expected result:
----------------
If the uploaded file is named "james_2003.jpg" and $_SESSION['username'] = "wilson" I expect the file to be saved on the server as "wilson_james_2003.jpg". 

Actual result:
--------------
File is saved simply as "_james_2003.jpg".  It correct appends"_", however, it doe not append $_SESSION['username'].