-----Original Message-----
What about the following?
http://support.microsoft.com/?kbid=231287
NOTE: Loopback is supported only in a purely Windows 2000
based environment.
Both the computer account and the user account must be in
Active Directory.
If a Microsoft Windows NT 4.0 based domain controller
manages either
account, the loopback does not function. The client
computer must be a
Windows 2000 based computer.
.