[Samba] Problems Rejoing Domain w/ WinXP & Samba 2.0.25b

[Marco J. Shmerykowsky, P.E.]

Just recovering from a update headache going from Samba 2.0.20 to
2.0.25b on Centos 4.5.  Prior to the update, Windows XP (on a 
brand new machine) was able to authenticate to the Samaba server.

After the upgrade to 2.0.25b, however, WinXP now gives the
following error:

The following error has occured attempting to join domain 'fubar'

The RPC server is unavailable.

My Win2000 Professional & OS/2 clients have no problem connecting.
I've been searching Google for leads, but haven't found anything
yet.

Suggestions? 

Thanks in Advance

Marco