samba - May 2003 - Cannot add groups to an ACL (no domain involved, only win2k client and samba server)

I  have  managed  to compile samba 2.2.8a for Debian with acl support, and
now  I  see the samba server's users and groups from a win2k client. I can
change  every permission, add and remove users. I can see groups, and even
delete   them from the ACL, but when I try to add a group (users) I get an
error  that  says "unable to lookup user names for display", and the
group
is   not   added.  Do  I have to use a domain to make this work, or must I
somehow  add groups to a specific samba conf, as for users? I use standard
(passwd + smbpasswd) auth.

Thanks a lot.

-- 
Best regards,
 Fabio                          mailto:liste@kurgan.org