I have the same problem with my indesit dishwasher its an ID535, i have removed the bottom to find the float switch but cannot find the cause of the leak, i will check foe over sudsing as suggested and maybe even add some salt now ! , i had the idea that the tablets had the salt rather than need it in the tank, This is a nearly new dishwasher and the instructions did not state the need for salt in the reservoir , there was plenty of Finish advertising with the dishwasher and lots of mentions of there being salt in the the tabs
thanks for the advice i have read , i will update this after a few test runs of my dishwasher