You might have the problem I had back in the July, Not sure so I'll just throw it out there.
In July I got an iPad and wanted to set up FaceTime for the first time since I have a 3gs (no FaceTime). However my AppleID would not work no matter how hard I tried.
After FOUR LONG HOURS on the phone with tech support, turns out I've been an Apple customer for too long. NOT EVEN KIDDING. My Apple ID was "too old" they said. But something about "old Apple ID's were grandfathered in". They had to go "behind the scenes" and make a Case # for both myself and my husband (which took days) and re-configure our Apple ID's. Mind you, we had previously had ZERO problems making purchases from the App store. About three days later, we got an email from Apple saying our IDs were ready.....from there on out, everything works great.
Sorry for not being able to be more clear. What I can tell you is that it I'm not THAT old of a customer.....I bought my first Mac/got my first Apple ID in about 2008. I believe the problem was MobileMe - and Apple User ID's (email addresses) got confused with MobileMe logins (strictly names) Again, sorry for not being more clear....it was all extremely confusing because we had no problems, until we purchased a new product. So if anyone previously (or currently uses) MobileMe, this could be part of the problem. It was a huge headache for us. Good luck!