Hi, guys,
Thanks for your responses, all of you. I'll try those suggestions.
Yes, Mr. Zammler, the Jaz drive--even in my current configuration, without these drivers and the ROM upgrade--will work as a removable-disk hard drive like it's supposed to (since it is one)--that is, that the computer will recognize when you eject the disk and reinsert it or put another one in. And yes, even with my problems, I can get this drive to boot the OS (fun!) without the drivers they're talking about. But I think what these guys are talking about is supposed to help my partially-working Amiga Jaz drive become a completely-working Amiga Jaz drive.
I've been baffled as to why I can sometimes format the disk and sometimes not, and then it will sometimes allow stuff to get copied to it just fine and then sometimes not (claiming to be unvalidated), so hopefully these fixes the others are mentioning really will work (of course--who wouldn't hope that?). We'll see...
Mike