Group mapping

[A. Pohl]

I have a Linux-Samba-PDC (Samba 2.1-prealpha) and many NT4-Workstations
(german).
If I map my Unix-Group (root, GID=0) to "Administratoren", Samba say's
"UNIX User apohl Primary Group is in the wrong domain! S-1-5-32-544".
What does it mean?
How must I configure Samba to become admin right's on the NT-workstations?

smb.conf:
---------
...
domain group map = /usr/local/samba/lib/domaingroup.mapping
...

domaingroup.mapping:
--------------------
root = "Administratoren"


Andreas