Troubleshooting an MKIV for my friend's 2004 X5 with MKIV DVD based Nav. The Nav simply said "Please insert a DVD" so i ejected his 2004 map DVD, and inserted my 2009.1 High DVD. Still not read... I then decided to upgrade the software (he wasn't running 4-1/00), and the CD read instantly and updated the OS as usual...

Any ideas? Could a worn laser not read DVD's but still read CD's OK?

Thanks!