I rembember getting this after adding a drive to the empeg. After some trial and error, I discovered that the drive cable would repeatedly come loose while reattaching the drive sled. After re-doing it about ten times, I was able to get the drive sled back on without yanking the cable loose. Problem solved.

If you haven't been mucking around in your empeg, it's probably as David said, a bad drive cable ... or the hotglue could have come unglued and the cable is flopping around or slightly loose.

Greg