The triggering of the anti flood system (polystyrene float and micro switch at the base of washer) due to water leak or spill (this device causes the washer to stop until the leak is cleared. This often happens if you try to use washing up liquid instead of a dishwasher tablet. You need to open up the base, mop up the water, the float will go down and the machine will work again :)
Lloyd Phillips, July 2010