hello..i purchased this unit off ebay...they said it functioned 100%...well after getting it hooked up and modded to of course...gott the ipod adapter xm cd working....but the dvd player will not read a disk keeps saying read error...tried the nav disks and the same thing appears....is the unit defective or did i do something wrong....any and all help welcomed thanks

sounds like a bad laser eye. maybe try blowing compressed air through the slot first to ensure its not just dust?