Problem with cookies and Windows/2000 Internet Explorer

I have been racking my head, pounding the internet, doing everything I can and I cannot seem to find anything that helps me resolve this issue. I have a number of sites that I run all using PHP (obviously) and I've been doing most of my testing using Mozilla. Just today a co-worker asked me why the site was broken and on further investigation I found that their system was not storing _ANY_ cookies from the site. Its a Windows 2000 system, and I saw the same behavior from IE 5, IE 5.5, and IE 6.0. It takes and saves cookies from a large majority of sites, just no the ones using PHP. I did a test where I even fresh compiled and used vanilla configuration files both an apache webserver and php 4.3.1. The server is available at: http://mana.kontrol-pad.net and the test script I wrote was test.php (source is available at http://mana.kontrol-pad.net/test.phps). I'm at wits end, has anybody ever encountered anything like this before? Nathan