I had the same issue a few weeks back. Turns out that EA released a new update without telling anyone. i guess this update made the older versions unplayable (I was running ver 1.0 or 1.05 at the time). To update, open the App store. Don't go through iTunes, I don't think you can update through there. In the App store, look under your Purchased tab. Should see all the various apps you've downloaded. Search for The Simpsons Tapped Out. Tap on that. That should take you to the game's app page. Hopefully, you'll see that the button you would normally tap to purchase now says "update". Tap that and it should update to the newest version.