Hi Rich,
Yes, we do have Active Directory at the back end.
Alas the LDAP filters you've specified haven't helped. I'm still seeing the same behavior - everything working except for the Load User by User Name test - user is found but group membership fails. I've run the queries by hand through ldapsearch at the shell, and confirmed by eye that they seem to be returning the correct data. I also tried removing the nested group property modifiers - the results appeared identical but the queries returned a little faster .
Unless you've other instant ideas then I think at this point I can wait until we've got a purchased license (grinding through the corporate works now) and then I'll open a support ticket. That way I can share some LDAP queries and results with you directly. We can update the thread here after that.
Cheers
phil