I have the same problem with the internal app error for the calendar, but also at the same time getting the 'device mem. full unable to send\recieve sms' notice.
I reflashed just 2days ago to solve the latter, yet here it is again!
I'm on the edge of getting rid of this device as i seem to be spending half my time just trying to get it to work properly!
Regardless,has anyone got any fixes??
Cheers