Other people have had this problem with LW 5 & WMP. Maybe it's a bug. You could ask over here (different forum, so you'll need to register there): LimeWire Forums

In the meantime, try VLC player... that seems to have fixed the prob for some.
http://www.gnutellaforums.com/genera...ng-videos.html

http://www.gnutellaforums.com/downlo...em-lw-5-a.html