Dear RoyG,
that error means the cookie is missing for unknown reason. maybe because timeout.
If you run the following example, does this issue happen to you?
<?php require_once "phpuploader/include_phpuploader.php" ?>
<?php session_start(); ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "
http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="
http://www.w3.org/1999/xhtml">
<head>
<title>PHP Upload - Simple Upload with Progress</title>
</head>
<body>
<div class="demo">
<?php
$uploader=new PhpUploader();
$uploader->MultipleFilesUpload=false;
$uploader->InsertText="Upload File";
$uploader->Render();
?>
</div>
</body>
</html>
Thanks for asking