Get yourself an OS disk - they can be downloaded from many places - and update your software.

Your's is very old, current version is 3-2/63

Make sure the CD image is Mode2 and that verify that the CD is burnt as Mode2 (Nero infotool tells you) BEFORE you insert the OS CD.

The MkIII nav will lock up with a Mode1 CD and cause you headaches to fix it.