I have had similar issues with 100mb zip drives in the pc world, so I think that the issue is not specific to the amiga.
I had a p3-500 with 2 harddrives on ide0, and a combo drive partnered with a 100mb zip drive on ide1.
The only way that I could get it to pass POST was to have the zip drive set as master, and the cdrom set as slave, with the cdrom on the center connector. All other combinations failed for me.
I'll double check this (my sister now has that computer) but I think that the iomega implementation of an ide device was slightly odd. Just try different combinations of master/slave/cableselect and orders of connection on the cable.
Regards,
Cathal.
