That is an interesting problem, if you cannot access the domain GPO you cannot access AD Small problem, right?
Just out of curiosity, did you try creating a couple of users. A regular user (and use "run as.." to open the mmc console) and a user with admin rights that is not admin (copy of domain administrator) and use those 2 accounts to see if you can access the GPOs. Remember that the account has to have domain admin. A coworker of mine created a admin account and thought it could change the AD with he forgot the domain admin rights and hence, he couldn't.
Other than that I can't suggest anything right now