I got some mp3s that sometimes just break up in the middle and sound like a million cats scratching up against a chaulkboard or something. Then when I hold it there and bring it back it sounds fine but then breaks up again. Is this a codec problem or something? I know its not the songs because when I rewind in wimamp it plays it fine. Also the kbps in wimamp keep switching between 128kbps and 32kbps. Whats the problem?