Hi Edward,
You still keep working on your PB100?
I had the same problem and could fix it swapping the 2.5” SCSI disk from a luckily available 2nd Powerbook.
As these 2.5” SCSI discs are hard to come by, I found a great source for a SCSI 2.5 to SD-Card converter:
http://www.artmix.com/SD_powermonster.html
But you need another working 68K Mac to prepare the SD-Card. But I’m sure you’ll find someone to bridge this difficulty.
Pete