Hmmm, that sounds really strange...If it occured on just one file every now and again, you would think it was just bad luck, but to do this all the time doesn't sound right...
It sounds like you keep connecting to either fake files or fake hosts...
Did you try searching for new ultrapeers??
Did you also apply the Hostile list ??
Try downloading PeerGuardian and enable it when ever you use Limewire or any p2p app...
Peerguardian __(FREE)