Hi:
I just bought an original boxed game for amiga, Falcon.
Is by spectrum holobyte.
I don't have an answer for you but I remember back when this was new it was a pain in the butt to get working because of the copy protection. It was real touchy with the drive alignment. If you were even slightly off it wouldn't work. I recall .info magazine talking about this and legit customers using cracked copies because they were more reliable.
Maybe try a cracked copy to see if that loads ok?
I wish you the best of luck though! :-)
-P