Have sessions changed in 5.2.1

I am having a problem with sessions on a server running 5.2.1. The software I have installed works fine on all servers accept this one and im guessing PHP is causing the issue. Has something changed in PHP 5.2.1 with the $_SESSION var.

Sessions are working on the server as I have written a test page to confirm this.

Please check this phpinfo() page: http://www.hitsplus.com/phptest.php

Thanks,
Bradley

There were some changes in 5.3 regarding the order of things at the end of execution but I don’t know about 5.2.1