allmost certain water in the base of the dishwasher
drain pump runs when you switch in on ,
pull the dishwasher out and slowly tilt it backwards ,water should be seen running out on to the floor ,put an old towel down to absorb the water, then stand the appliance on all four feet ,open the door and check the the bottom wash arm support is not loose ,you can tighten it with your hand , its the part bellow the wash arm that screws into the wash motor casing , if its loose water leaks into the base and triggers the overfill device.
will crossan, August 2010