I've got a 7520 that when I try to start the calendar all I get is:

Error Starting net_rim_bb_calendar_app:Class
'net.rim.device.api.synchroniztaion.UIDGumbator' not found.

Any ideas on how to fix this?

Device has v4.1.0.380 loaded on it.

Thanks!

Have you tried removing the battery and then putting it back in?

Yes. Tried that twice now. Still getting the message.

Thanks though. Anything else to try?

Try reloading the handheld OS.

Searching now to find out how to wipre and reload the OS.