wincvs to cvs via pserver "encountered a problem" during login
 

I recently installed cvs server on suse 9.2, and it has been working fine for a couple of days with WinCVS 1.3.8.1 on Windows XP Pro.
In attempting to give administrative cvsroot access to a coworker today, I am all of a sudden getting a dialog box entitled "CVS NT Client/Server" saying "CVS NT Client/Server has encountered a problem and needs to close. We are sorry for the inconvenience."
The login fails.
What the heck did I do?
I can't update to a later client yet, because my users are using "local" access across the LAN, and later clients don't work that way (which is why I'm trying to set up pserver in the first place).

Help, please!