It happens to the newest & most popular songs! Have a look at this:
http://www.gnutellaforums.com/showth...threadid=28801
Basically try to stay away from T3 sources. Check the bitrate v's size of the file. That's frequently one way of knowing the file will be corrupt. If there's some the same size but different bit-rate, then they or some of those sources will be corrupt.