Hello Mark,
What OS are your client machines?
Are you using ISA or the RDP Client?
Do you have a 2000 TS Licensing Server in your environment? If yes, where
is it installed (member server or DC?)
Things to check
===========
A. 329896 Error Message: Because of a Security Error, the Client Could Not
Connect
http://support.microsoft.com/?id=329896Follow steps in article below:
B. Verify the permissions in the registry on the Terminal Server Client
computer:
a. Start Registry Editor (Regedt32.exe).
b. Locate the following key in the registry:
HKEY_LOCAL_MACHINE\Software\Microsoft\MSLicensing\Store\LICENSE00x
c. Click Security, and then click Permissions.
d. Set the permission for Everyone to Full, and then click OK.
e. Quit Registry Editor and Test.
C. Follow steps in article below on one of the client machines:
329888 "Error Connecting to Terminal Server: <ServerName>" Error Message
Occurs
http://support.microsoft.com/?id=329888
Thank You.
Diana.