Cannot find domain primary controller

[Skidmore, Stanley G]

Good morning,
I have Samba 2.0.6 installed on Redhat Linux 6.1. When I attempt to join the domain I receive a message that states the the primary domain contraoller cannot be located.

I have created the encrypted smbpasswd file, added my machine name (client$) to smbpasswd with smbpasswd -a -m client. Server manager on the NT side shows Samba as a PDC. Communications between both machines is good with ping's by name and i.p. address working fine. 

I can also map drive drives on Samba but cannot join the domain.

Does anyone have any idea what might be causing this?