I had this, I found a button an a lolly stick jamming the pump.
On the bottom of the machine is a panel with 2 plastic catches, remove this. Then find a thin drain pipe with a plastic bung. Get a bowl and remove the bung. The you can unscrew the pump cover. this is on the right hand side and you just undo it by hand. When things are stuck it might be a bit difficult to pull out. Yank it out and remove any blockage, if you are lucky the impeller blades will be ok.
Steven, February 2006