If anyone has any insight to where I could look for this problem..

NW6.5 SP5 server with a replica of partitioned OU it exists in.
A user account, in the same partition as the server, with full supervisory rights to the OU (and thus the Server object) fails to Authenticate in NoRM.

A User account with Supervisory rights inherited from above authenticate with no problem.

no IRF's are in use from what i can tell