I'm getting this too, on WinXP with Firefox 1.5 and, after upgrade, on 2.0. From a clean start (SR cookies deleted and cache cleared, system reboot) I get the front page and my ID/password is not automagically inserted, as expected with no cookies. When I log in, I get a 'welcome AndyG' screen which redirects after a few seconds to this error message:
You would need to provide your own index.php if they don't have to use the home module, because the index.php included with vbportal, just sends them here. If you followed a valid link, please notify the webmaster