I would like to second this please.
I have the same problem the tablets I brought my kids work but will not allow download from the market. various messages like:
Error Retrieving information from server. [RPC:S-5:AEC-0]
Download not allowed in your country....WTF?!
Error 403 on attempt to update stock apps.
I have tried the fix for the RPC error of delete the user reboot and re-enter user which doesn't work. I have cleared the cache of the location services but it still comes up with the country issue.
I already have one which works perfectly and my wifes also works fine. I was thinking would it be a good idea to try and extract the firmware from my wifes/mine then reload onto the kids tablets?
my build is:
nuclear_pfdq88-eng 4.0.3 IML74K 20120609 test-keys
my wifes (which is working but far too big letters/icons):
nuclear_evb-eng 4.0.4 IMM76D 20121108
my kids (play hates and massive letters/icons):
I have posted this in another forum but after nearly 300 reads and no replies (not even sarcastic techie ones!!) I have given up on that forum.
Obviously if this works then I will post the firmware on the forum to help noobs like my self