[Zope] 500 error from windows only!

[Gregory Dudek]

  Synopsis: only windows users are getting a 500 error when they
should get a login screen!

  I'm running a zope site and using the (deprecated but easy)
Generic User Folder for cookie mode login (although that product
may not be the issue).

  Many (all?) users from explorer on windows currently get a 
500 Server Error when they get to a page that needs authentication.
  Users from any "normal" OS like linux or MacOS (9 or X) using
either netscape, explorer or mozilla get a nice normal login
screen.

  How is it possible the only windows users are getting the 500 error
screen and might anybody have a hint re. how to fix this?  There is 
nothing interesting in the logs.

  If you want to see this for yourself, it's visible at:
     http://www.mudcritters.com
(it's a not-for profit kids gaming site that's suppoed to sneak
them educational material.)

  Thanks, Greg