Some files are simply out of sync, however, if this occurs with many files, I would not think that is the case. Have you checked any of the files with Bitzi? That's a pretty good way to determine if a file is good.
http://www.gnutellaforums.com/showth...threadid=37676
These files are acting this way right after you download them, right? You're not converting the movies or anything like that?
It sounds like perhaps your computer isn't keeping up. Are you running multiple programs? Look in the task manager and see how much CPU Limewire and other programs are using.
Good Luck
Dan