I'm surprised by the emplode and jemplode issues you describe. That's the first I've heard anyone mention that happening.

Emplode 2.10 ... Well that's got known issues and shouldn't be used anyway. (only 2.00 is known to be stable.) But Jemplode should do just fine, so I'm surprised. First I'd look to make sure that the shell thinks you've got 250gb there. Vital signs might be reading the IDE hardware directly. I don't know the command required at the shell to show the disk size of drive0, but I'm sure someone here can help with that.

Next, if the shell really reports 250gb, then I'm curious about exactly what goes wrong with jemplode, i.e., exactly what you're loading and how, and exactly what error jemplode is giving.