My.User.IsInRole("Role Name") Throws A Trust Relationship Error On Windows 7

Problem: My programs throw a Trust Relationship error when calling My.User.IsInRole() but only on Windows 7 64 bits. They work on all our Windows XP stations. My code is pretty simple.

With My.User
if .IsInRole("Some Security Group Name") Then
Bla.. Bla.. Bla..
End If
End With

I'm the only one in the company using Windows 7 which we are evaluating to decide if/when we're going to upgrade all our PC's. I am a domain administrator and my PC is in the domain and I'm authenticated. Since I installed Win 7 I haven't had any other authentication issues. The apps are built on .NET 2.0 SP2 I don't know much about our domain setup which is handled by our network administrator but I'm told that the Primary Controller is a Windows 2003 and the Secondary is Windows 2000. He tells me that by default every workstation first authenticate on the Secondary controller if it's available.

Here's the StackTrace

System.SystemException was unhandled
Message="The trust relationship between this workstation and the primary domain failed.
" Source="mscorlib"
StackTrace:

[code]....