My /cache is empty at the moment. Try looking in /sdcard/Music with a file browser app on the phone.
If you need a file browser, try ASTRO File Manager. To see files down at root level select All and keep going up if you aren't already at the root, then find /sdcard (really a misnomer; /sdcard is actually in the phone's internal Flash, not on a card), where you should see Music. If you also have an SD card in the phone, you might also see folder /sdcard-ext, which represents the physical SD card content.
You could also plug the phone into a desktop USB port and navigate the phone's files on the desktop. In that case the true phone root won't be visible, so you should see folder Music directly.
I'll need to play with it more but, as I recall, none of those phone folder names appear on the vehicle console screen so navigating the files structure is different on the phone and on the console screen. Still, you should be able to locate the mp3s, even if only by name.
'97 528it, '99 X5, '03 X5, '04 528i, '05 X5, '05 330ci, '07 X5, '07 X3, '13 X3, '15 328xi
Last edited by GTBecker; 01-22-2013 at 10:32 AM.