It's probably too late for you now, but when ours did that an engineer fixed it by doing the following:
open the panel on the bottom right
pull out the black tube with the blue lid on
when you take the lid off, all the water will drain (eventually) out
once the water has all drained, replace the tube
then twist the cap on the right (the fluff filter)
empty this as this is the blockage which is causing the pump to fail, thereby preventing the water from draining
me
December 2009