I just rang Indeist and they suggested checking the outlet pipe is not blocked and draining the machine by returning it to floor level. Then remove the lower, front panel to access the filter (lower right). Put down some old towels and slowly unscrew the filter. Once all the water has stopped then remove the filter fully and clean. Put everything back in its place. Resetting the machine should then resolve the problem.
Peter Steward, December 2007