"fille system error"
If it is a certain file, or a group of files, i would delete all audio from the media player, and read the system handbook, to see all compatible files, and buy a converter to convert them the the right file format. some converters are AVI, which I would recommend. When i bought it, it was around $20. Most likely you Mp3 plays (besides MP3 format) a windows media player format, since Windows Media Player even has a sync button to download songs quickly to your audio device. If your files were in the right format, then they might have been corrupted, or invalid, meaning they had information missing, or they werent correct with the codes. So I would just re-load them.