diplomat adp8352 dishwasher inop?

hi there i have a diplomat adp8352 dishwasher. when i set it to the 3rd wash programme( 3 red lights) it turns on and starts working. after a period of time the macine starts beeping and red lights start flashing 1+2. there is no water underneath and have made sure that the drain pipe isnt blocked. can anyone help please?