Terminal Service Error

I have a Windows 2000 Server with terminal services installed and it was working for about 7 months. About a month ago, certain Windows XP Pro workstations suddenly started getting “The session was disconnected due to an error in the licensing protocol.”

I have tried order that protocols bind, reinstalling, reactivating the license, took it out of server mode and put it back in, rebooted, everything except the registry hack, but am going to resort to that if no one has any other suggestions.

It suddenly starting spreading to other workstations and now no one can remote desktop into that box. Thanks for your help, anyone!