SE Ericsson w380 imported mp3s "playback failed"

I purchased a used Sony Ericsson w380i, or w380a in some circles, to be used as a replacement for a stolen cheap Nokia flip phone I had. I thought it would be a good deal. Its compact and works as a walkman as well. Only trouble is, besides the exterior screen not working :(, is that imported mp3s from my Mac with Media Sync from my iTunes library will only start to play one or two songs and then even they stop playing. One started with only one channel working, most songs don't play at all. All I get is "playback failed" for every song eventually. Will a firmware flash fix this? And which one? Or do I need to filter the mp3s or change their format first? Please help.