How you making out with this one ?

Your problem has me facinated and I'm trying like the dickens to find a similar environment over here to replicate your problem.

Just to clarify things alittle...

You have a master domain and a resource domain with full two way trust (or is there only a one-way trust with resource domain trusting master) ?

Your logging into a workstation that is joined to the resource domain with a master domain user account.

My gut feelings still says something to do with access violation. When you try this on Windows NT - you mentioned ingroup() returns a zero, what is the value of @ERROR ?

Shawn.