Make sure you don't have too many plates etc around the area infront of the dispenser - as how it works is that the water is meant to spray up at the door of the dispenser at a particular time - it opens and the tablet is dispersed correctly at the right time. If you have too many things in the 'firing line' it does not open when it should and you end up with the tablet all mucky in the dispenser or sitting on the floor of the dishwasher and your crockery etc hasn't cleaned properly - try it. I had this problem too until I changed where I placed certain things.
toni, June 2012