You might find the bottom filter's blocked. Take out the bottom rotor arm (it unclips and pulls out). Turn (undo) the grey collar on the pillar you just took the rotor off, and you should find that the whole circular bottom plate (perforated like a collander) comes off.
You may well find all sorts of gunk either in the holes in the plate itself, or underneath. Also, check the cyclindrical filter 'embedded' in the bottom plate (it just pulls out) as this gets blocked easily by bits of food etc (it's job is to trap it).
This is described in the Instruction manual - if you don't have one you can doenload it from the Serviceforce website: checkout www.serviceforce.co.uk/index.asp, click on 'Instruction manuals' and enter 'DW925' in the 'Guide Me' search box.
Otherwise, one other thought is that your waste pipe may be blocked, possibly at the outlet end, depending on where it empties. Or the pump is poorly.
GladToBeGrey, November 2005