Hotpoint Aquarius FDW60 wont work?

Hi, I have recently had to replace the door lock on my Hotpoint Aquarius FDW60 dishwasher. The machine worked fine for a few washes however, it has now stopped working altogether.
What happens is, after loading the machine and pressing the start button it fills with water, then it runs for about 30 seconds, then it empties then both the ECO and PRE-WASH buttons flash on and off (the Pre-wash button in the program selection group of buttons).
I have also noticed the the bottom spray rotor appears to be loose.
Could you help please

Many thanks