Well, I'm trying to unhide a hidden update so that I can check how to rehide it, but I can't figure out how to unhide it! SorryHmm. If nobody else responds then I'll check when I get home.
I've had it prompt me to install updates for legitimately purchased apps that I've previously had installed. There's no reason to assume that the OP has pirated Angry Birds.That's a known issue for people who have pirated app store apps installed. An update to Angry Birds is listed, but you can't update it due to the fact that it asks for the password to someone else's account.