It is to do with the tube that goes out of the back of the machine to where it goes in to the drain. Either it is twisted or blocked somehow,or is too long or goes up and down too many times for the pump inside the machine to be able to push water through it. If you have a new machine and this is the first time it has happened... have you put the machine in to one of those gaps they make in new homes? These are too narrow for a machine and the tubes! You will need to pull the machine forwards by about 10-15cm to give the tubes at the back a chance to work properly without being squashed at the back.
Zanussi owner from Cheshire, December 2004