My Diplomat ADP8352 doesn't drain?

My dishwasher has stopped working- The program starts and several minutes later stops and beeps continusly for about 15 seconds then stops and seems to beep off and on until the door is opened. It seems to be that there is a collection of water in the bottom of the dishwasher which doesn't drain and this stops the program from continuing. I have tried removing the water and reseting the dishwasher but to no avail - any ideas please