Obvious problem:
You are passing the 8Mb Zorro memory space and you don't need 3 SCSI controllers on the same machine.
To really solve it: buy another SCSI cable with enough connectors plus one for active terminator. Take the 2090 and 2091 cards out. Create a folded plastic thick enough to hold the two "remaining" HD over the Zorro slots. Remember you need to use just one different SCSI ID on each drive (remember to take the terminator resistor packs on all disks!).
