Difficulty getting to the Main Screen
The reason for this is that you most likely have the update for the iPod touch, all that you need to do is remove it from your multi-tasking list. What happens is that since the list makes it available to you to begin where you left off, the game doesn't REALLY close. So if you delete it from the multi-tasking list, it should be fine. This is the only cause that I have noticed so far. If you find the same problem, but take my advice and it still won't work, I would recommend that you email support using the in-game "Help" button.
I hope this helps at least someone out.
BSF FOR LIFE!!!