your sequencing mechanism is jammed. take off the black plastic splash board at bottom front of dishwasher (make sure you unplug machine 1st). To the left you will see a metal component with wires coming out of top (sequencing unit). In the centre you will see a plastic spindle (mine is green) turn this with a pair of pliers one click clockwise, that should free it. Try the machine again. Each click clockwise is a sequence in the cycle. When the arrow is pointing up at the 12 oclock position then the machine should switch off. If the fault keeps happening try a new timing unit from INTER-SPARES on the net.
Craig Hunt, December 2006