I have been having the same problem with updating my apps on iphone 4s.
a message comes up and says "Account not in this Store" and my account is not valid for use in the U.S. store!!
I have never purchased anything from the US app store. This problem only happened when I updated the iphone last week!!
Can someone help?
On my itune account I am already registered in the UK setting.
Come on Apple whats going on with your recent updates!!