Hiya and welcome...
Sorry about that edit on your first post, but rules are rules !
re: Your problem... Please have a BIG search around these Gnutellaforums for posts related to the same subject...
There are 100's and 100's of them.
You have probably fallen victim to the same problem as many others...
There are people out there who are deliberately offering corrupted files to the p2p community.
If you read other's posts here ypu will quickly learn who the regular culprits are.
HINT > They are large corporations.