To produce a Mac usable floppy disk on a PC follow the instructions given in our 68kMLA Wiki -> HFVExplorer.
You might also try to connect the iomega disk drive with inserted HFS formatted disk to your Mac, drive ready while booting. Probably this will cause an appropriate drive to load during the boot process without an iomega extension. As well, it is possible to use other disk formatting tools for the iomega zip drives, like HDT (FWB harddisk toolkit).
P.S.: make sure you have got a SCSI version of the zip drive; the Parallel Port version for PCs might sport a connector of the same physical dimensions, but experiments to connect this to a SCSI port are strictly forbidden ;-)
You might also try to connect the iomega disk drive with inserted HFS formatted disk to your Mac, drive ready while booting. Probably this will cause an appropriate drive to load during the boot process without an iomega extension. As well, it is possible to use other disk formatting tools for the iomega zip drives, like HDT (FWB harddisk toolkit).
P.S.: make sure you have got a SCSI version of the zip drive; the Parallel Port version for PCs might sport a connector of the same physical dimensions, but experiments to connect this to a SCSI port are strictly forbidden ;-)