Use good quality Rinse Aid - it helps the rinsing water drain off properly - if it doesn't drain off, broken down bits of food debris remain in the rinsing droplets and get baked on hard during the drying process - any dirst on the crocks at the end of washing must be food debris that went in the machine on the crockery - it may help to scrape off any big lumps before loading.
Good luck...
Peccavi
November 2009