the door will not open until the machine sees that it is empty of water. theres probably a problem with your drain pump, either it isnt working at all or not properly. select a drain cycle and see if that gets the door to open. if it doesnt then youll need to take the waste pipe out of the drain and put it lower than the wash drum. this will allow the machine to drain out with the aid of gravity (god bless isaac newton :P) then you should be able to open the door after the machine has detected no water. you might need to isolate on the wall and allow a few minutes before turning back on to reset the programmer.
next you should take the filter out of the drain pump. it may still be ok, just possibly have something like a penny caught up in it. clean out and try again. be prepared for a little water to go on the floor when doing this...it can be a wet job.
tony
January 2009