For anyone else looking into this, I had a similar problem with my Whirlpool ADP 4403. It simply stopped working after the initial fill-up cycle, didn't release the dishwasher tablet and the green light flashed continuously (in fact, it was flashing in a cycle of 8, pause, 8, pause...)
To fix it, I simply closed the dishwasher door and, with the On/Off button switched on, held the Start button down for many seconds.
The dishwasher then gurgled into life and completed the cycle and everything is now fine.
Al, August 2010