Whats the name of the beast? Does it have the littel PCB attached at its end? Or is your cable altered to match the diffent pinsignals?
Boot without startup-sequence and put a disk with the copy command on it eg Workbenchdisk into the drive, then do:
1. df0:c/copy df0:c/copy to RAM: (putting "copy command into ramdisk)
2. df0:cd ram:
3. Insert the disk with the problemmaker into df0:
4. copy df0:name-of-troublemaker dh0:(your destination-dir)
Does the error happen again?
Markus