I'll send you by private message a URL to a par2 set. Use quickpar (Google search if you don't already know what it is) and run it against the bas ISO. If there are enough recovery blocks to fix your ISO then quickpar can repair it, otherwise you'll at least know how bad the damage is.

What version(s) of BitTorrent were you using? I downloaded the torrent with 4.0.3 of BitTorrent on an old Win98 system with FAT partitions and had no problems, obviously many other BitTorrent users are having good results too. It would be interesting to know what is going wrong in your case.