Provisioning profile expiring soon dialog won't dismiss
I just had the same thing - iPad2 running 4.3.3. It renders the iPad completely unusable.

I was able to make it go away by deleting the offending profile from the device using Organizer (part of Xcode on Mac), then doing a reset (holding down sleep/wake button and home button for 10 seconds).

The iPad rebooted and everything was fine, no restore required. If you're using Windows you might be able to delete the profile using Apple's iPhone Configuration Utility: DL1466