A great percentage of the time, trying to reprogram it (using a real RIB and cable, not one of those knock-off aftermarket RIB-less cables) with a saved codeplug from that radio will bring it back to life. I've had it happen several times, and unfortunately for me, it took a couple of these errors to make me ditch that stupid aftermarket RIBless thing and use standard RIB + Cable, so I hope that's not the predicament you're in.
-Josh