Hi cha16,
Welcome to the Apple Support Communities!
The first suggestion I have for you will help you isolate and troubleshoot this issue. First, you should try to reset the iOS device by following these instructions:
iOS: Turning off and on (restarting) and resetting
http://support.apple.com/kb/ht1430
Next if you are still experiencing issues after attempting that troubleshooting step, I suggest force closing the application and trying again.
iOS: Force an app to close
http://support.apple.com/kb/ht5137
Please let me know if you need further assistance.
Have a great day,
-Joe