You could try return the disk to Amiga Inc. for a replacement.
Amiga, Inc.
Attn: John Grzymala
167 Madison Avenue
Suite 301
New York, NY 10016
Even though you own the original disk it's still illegal to download an ADF - you could have made an ADF of your own disk while it was still working, but downloading an ADF of someone else's isn't allowed.
