1) blocked drain filter.
2) faulty drain pump.
remove the excess water by the drain hose, place end into a bowl and lower to the ground water should flow out by gravity.
When water has stopped remove the hose that leaves the bottom of the outer drum and clean the filter
and reassemble doing this might solve your problem, but might as well clean the drain pump out at the same time. also check it operation.
As a new pump may be required.
wirecutterman
April 2009