It is probable that the microswitch in the doorlock is worn-out. If that switch doesn't close correctly, then the program will not start. It is possible to lubricate the switch with silicon. You have to do some disassembly to get at it. And it may not solve the problem. According to Miele, you have to buy a whole new lock mechanism. But it may be possible to replace only the switch if you take the old one to a good electronics component store.
Rolf, Stockholm Sweden, April 2007