Also had this problem, my anti-flood switch wasn't 'resetting'.
When the base fills with water the anti-flood switch will close the water intake valve.
When you tilt the dishwasher to empty and the anti-flood switch doesn't reset then the 1st light fault will start.
Put the machine on its side unscrew the 4x screws from the base plate.
Here you will find the anti-flood switch with the polystyrene float, just check it 'switches' correctly and put back together.
This worked for me on a 10 year old Indesit D41, try this before buying a new inlet valve.
Craig, June 2012