Can not add members to the Local Admin group

Archived from groups: microsoft.public.win2000.advanced_server (More info?)

Quick background; I had setup my source domain and my
target domain and was able to use ADMT and run a few test
migrations, worked fine.
The PDC was a bout to die, so we demoted it to a BDC and
then took it off line. We built a new stand-alone got it
working fine (e.g. gave it the same name and IP address as
the old PDC). Made it a BDC and then promoted it to the
PDC.
Now I have gone back to make sure that ADMT is working, I
can setup the trusts just fine. But when I try to add the
global Admin group from the NT domain to the Local Admin
group in the AD domain, I am having two issues. The first
time I tried I got an error message "that the group was
already a member to this group". The next time I tried
the group is added (Icon changes) but when I close and
reopen "users & Computers" and open the Admin group I see
that the NT-Admin group has the RED arrow and the group
has not added.

Please any Help would be greatly appreciated.