One problem related to door latch has been reported for the 2001 Mercedes Benz 320. The most recently reported issues are listed below.
When I bought the car, I was told it was held up at the port because customs would not clear it until the rear door locks were replaced and made to work independenlty. Neither works independently. Door must be unlocked in order for latch to work (like when child safety switch is on). Further, if passenger tries to open the latch at the same time the driver is unlocking the door with the button on the dash, the latch will not release. If the doors are relocked and unlocked, sometimes the latch will reengage. Other times the door must be opened from the outside. I am a dot employee and drive a carpool on occasion so can make arrangements to show it to you.