I think Radar Contact is on the right track. MP3 is just a compressed file format - it takes the standard CDDA type file (which CD players expect) and compresses it to around 10%. When the MP3 files were burned onto the CD was the format also converted? Using a standard CD player to read an MP3 file is like trying to use Microsoft Word to open an Excel spreadsheet! There a chance that the MP3's have just been stored on your CD in the manner you would store backup data from the computer.