Geggyta516 and thenthroot, if you have a large number of actions in your OmniFocus database, the phone can run out of memory trying to load them all, which causes the app to quit.
The latest sneakypeek builds of OmniFocus 1.1 include a new 'Move Old Data to Archive...' item under the File menu.
I'd recommend backing up your database, archiving some old actions (I archived everything completed more than six months ago), synching, and then restarting the phone app.
If that doesn't help, please let us know. If there are any process with the archive process, please let us know. (If there are any problems, you can use "Revert to Database Backup" to put everything back the way it was at the beginning of the process.)