I have an identical problem.

Installed CuteChat for CS2.0 with .NET Framework 2.0

http://emrupdate.com/chat.aspx

Running a single Chat Room, members only, no anonymous, no whipsers, no file upload, max 50.

After a successful chat - returning later to the chat room - we get redirected to our custom Error Page.
I can resurrect the chat room by touching web.config. Something missing or is a permission not set.

Any ideas?
Nick