Vicky, you can report issues at http://forums.filemaker.com/hives/1eea103f05/summary. To fix this issue, I have to sometimes shutdown the iPad and restart. I'm using an iPad 2 and it would be interesting to know if newer iPad experience this problem.
In my case, nothing except killing and reinstalling the app has worked. I've tried shutting down the iPad and restarting, nope. I don't feel like talking field people through reinstalling the app, you know? They shouldn't have to do stuff like that.