Try using another player. The LW player tends to skip, pop, and generally mess up, and is really only good for previewing files.
Open LW and go to Tools>Options>Player, untick the box by "Use LimeWire Media Player" > Apply > OK. Your songs will now launch in your default player.
I use
winamp but there are plenty of others out there. A good backup player is
VLC media player, it has the codecs built in and will play most file types.
CODECs list for Movies/Alternate players / Video help forums/ video-mp3 fixers How to set the Default applications