Might be the formatting of your SD card -- if you're using it on a PC most of the time its NTFS file format -- most car stereos prefer FAT32
For windows 7:
Pretty easy fix, insert SD card into your PC
click windows icon, type in "Format", click "Create and Format hardisk partitions"
Find your SD card from the list once it populates, follow along, format it from NTFS to FAT32
EDIT:
Ya, SD card needs to be FAT32
http://forums.vwvortex.com/showthrea...-510-SD-Format