why doesn´t washing machine start?

why doesn´t washing machine start?

Its a P853 Samsung, and it gives an error code dE which is a door error. We have held the door firmly shut but no dice. I suppose the sensor switch inside the door latch point on the front of the machine is supposed to sense when the door is shut and tells the motor its ok to begin the wash program. We have tried pushing the sensor switch fully to the left but it still gives the dE code. Does anyone know how to fix this?
Thanks very much,

Carlos

April 2011