I had the same problem, after my wife put in a bathmat to wash the machine became unlevel and danced around the floor until she stopped it. But then it wouldn't startup again. Got the code "ddo" took the top and front cover off and found that on the right side of the detergent drawer opening there was a magnetic sensor (that had come lose in the dance), with a magnet mounted behind the detergent drawer front on the right side. Glued the sensor back in place and everything works fine.
greg, March 2009