You need to narrow down the source of the problem. It might just be a bug in the beta player software, or it might be that the files are somehow bad on your PC's hard disk. It also could be a simple case of a bad/loose cable as described here.

First, I would recommend downgrading the player/emplode to 1.03 which is known to be stable. Then I would check to make sure there's disk space free on the player, just in case the problem was a lack of disk space on the player.

Finally, I would use these tools to see if the MP3s themselves are somehow having a problem on the PC's hard disk.