Solved the problem
After re-mounting the DVD/NAVI unit without the CD it sounded wierd
It was the motor for the drive that wasn't mounted correctly (gear wasn't engaged)
After fixing that and once more re-mounting the DVD/NAVI unit, the screen was blank.
Thank god it accepted the previous modified CD and I am now back
running version 10.00 modified with own splashscreen.

Back is to figure out what went wrong
1 the modifications I made to navboot caused the error
2 bad CD - used same brand as the working ones.... will try a new one