This is a single server installation of Team Server and I did the installation with the DOMAIN\tfsservice account as well as using that name for the service account.
The installation was done exactly according to specs with SQL 2005 sharepoint, etc.
After installation was finished, I went to add another domain user as a namespace administrator, and got this response.
C:\Program Files\Microsoft Visual Studio 2005 Enterprise Server\BISIISDIR\sdk
n>gssutil /g+ adm: n:DOMAIN\stacyd
GSSUTIL - TFS Group Security Client Tool
(c)Copyright, Microsoft Corporation, 2004. All rights reserved.
Connecting to the TFS web service...
Resolving identity "adm:"...
a [GLOBAL]\Namespace Administrators
Resolving identity "n:DOMAIN\stacyd"...
FATAL ERROR: There was a problem on the server of unknown cause. See the TFS
rver log file for details. Time: 2005-05-17T13:50:49:658

and then this in the eventviewer:
EventType teamfoundationue, P1 1.0.0.0, P2 tfs, P3 v2.0.50215, P4 8.0.0.0, P5 elead, P6 9c40306e, P7 6d0a6670, P8 2c12fee2, P9 NIL, P10 NIL.
If I do doubleslashes for the name (which is suggested by the inline help), I get this:
FATAL ERROR: The specified project is not registered.

If I start up the TF Client and connect as the tfsservice account I can create projects and everything is happily, but I cannot add a user through the gui either. The dialog will die with the same event if I try to add a domain user to the namespace administrators account.
Any ideas? Thanks in advance