samba - Jan 2006 - Granting rights to w2k domain's workstations

Hello,
 
I am a new user in Suse Linux/Samba. I deseperatly try to grant
Administrator's and Power user's rights on my domain
user's W2000 workstations. I use Sles9 sp3 Samba 3.020b ans LDAP. I have
readed that I shoud use:
net rpc group addmem "Administrators" "Domain Users"...
 
I get: 
Could not loockup group member Domain users
Could not add Domain users to Administrators: NT_STATUS_NONE_MAPPED
 
With the "getent group" command I get all the Linux group, but not the
default NT group
 
For mapping the NT to Linux groups I then tryed: net groupmap add
ntgroup="Domain Admins" unixgroup=ntadmin
 
I get:
No rid or sid specified, choosing algorithmic mapping
adding entry for group Domain Admins failed!
 
Same second error message if I add rid=512 at the end of the command line.
 
With the command "net groupmap list, only my the LDAP's groups appear.
 
Finaly I am a bit confused with all the versions of Samba, Ldap and Suse. Many
documents refered to obsolete commands
What's wrong ?
 
thanks in advance
Roland Burger