I had this problem, I found the answer elsewhere on the web.
In our case it was a blocked filter. Unfortunatly, on this model the filter is not easily accessable. You have to remove the white plastic panel at the rear of the machine. On the right hand side you will see a black rubber casing which sits under the drum and connects to the pump (pump has grey drain pipe coming from it). Undo the plastic jubilee clip around the top of the black rubber casing - watch out as this will be full of water. I propped my machine on some books so I could get a washing up bowl underneath. Don't worry about the other connections to the black rubber case they are flexible and will allow for movement. Inside the black rubber casing is a plastic ball which sits in plastic cup - clean all the debris out of this - we had hair clips, coins, plastic wrappers etc. Now just put back together in reverse. Thats it - good luck.
Webo, June 2009