I just bought a Juke yesterday.
I had the same problems that many others in this thread had - plugged it in once, worked fine, next time, no dice. I tried the partition thing, and I was confident that it had worked, but after plugging the Juke in for about the fourth time after the partition, it went back to zero everything.
It's quite frustrating, and I don't know if partitioning the device will harm it, but I just ran my third partition. Does anyone know why this keeps happening?