My dishwasher got stuck because the aquastop wasn't opening. Try GENTLY pushing a rod (the size of a pencil and NOT sharp!) in the hole underneath the solenoid. If this has no result gently tap the solenoid with a small hammer(!). This is of course no long-term solution, but might tide you over before you get around to repairing properly.
                 Mr. Saxman
                
 July 2005