You're playing it with LW's media player right? LW's media player is not so great at present (the new beta has an improved player.) Because LW's primary & priority functions are for dwnlding, searching, recording & listing data, LW's media player tends not to always play so well.

My recommendation is to disable LW's media player & then your default mp3 player will play instead! (Go to LW's menu Tools-Options & Player & Untick option box.) If I may suggest a good player that doesn't need xtra codecs to play all the different types of mp3 then try QCD (it's free): http://www.quinnware.com/ If you're not sure how to set a player as the default: find an mp3 in the finder on your computer, select it & go to File-Properties & select Opens with: Change to whatever you'd prefer.