It sounds like you might be using LimeWire's built in MP3 player. This is not the worlds greatest (or most efficient) player. I suggest you get a stand-alone media/audio player and use that instead. If you still get problems in playback it could be the files themselves.

If you are using a PC - go to www.winamp.com and download winamp - if the files don't play back smoothly then the files are stuffed. If they do then change players from whatever you are using now. If you aren't using a Windows operating system then... I can't help.

Mark