This happened to me twice. One of the door lock actuators was defective and causing the circuit to overload burning out one of the fuses. Believe it or not, there are 3 fuses that are used to guard different aspects of the lock system. Way to go BMW on a nice, simple design. The dealer finally figured out which actuator was the culprit on my second visit. It's been about a year since I had this fixed and so far so good.
2007 BMW 335xi 6MT TiAg