user rights issue with DB application

I have created a local group and given it the same user rights as (local) admins under both domain controller policy and local policy (explicitly, not just inherited). I have also given this group full control permissions to a share. When I add a user to Domain Admins, he is able to use the application. When I add him to the global group I’ve created (of which the local group above is a member), I get all kings of crappy application errors. Anything else this could be besides a programming issue?