[Samba] Samba/LDAP User add problem...

[listserv.traffic at sloop.net]

I think I've got everything setup, and when i try to add a user to
samba, I get the following error.
---
smbldap-useradd -a -m -c "Greg Sloop" gregs
Error: SID not set for unix group 513
check if your unix group is mapped to an NT group

---
When I view the Domain Users group in the LDAP tree, the GID of 513 is
set. I'm sure this is something dumb on my comprehension part, but I
just don't see it. Perhaps someone can enlighten me.

Details:
-----
FC5,
Samba 3.0.22
LDAP, 2.3.19
smbldap-tools, 0.9.2