GB, are you choosing the 'Audio Disk' setup in your burning software? To create an audio disk, the files must be wave format, 44.1 khz stereo. Anything else will fail. To add files of other formats to a CD, the CD must be burned as a 'Data CD.' However, such a CD wouldn't work in an audio CD player, if that's what you're using on your commute. However, all is not lost. Probably some of the software you already have will convert the files to the proper format. They won't gain any fidelity of course, and they'll take up more space than the lower quality formats, but they will burn.