Zanussi DE6744 Dishwasher leaking?

My DE6744 dishwasher is leaking from the blue plastic component found on the left behind the side panel. The water overflows during the fill stage. There is a section halfway up on the left of this unit which appears to be a brown liquid? is this supposed to be there or is it just water that is stuck. I believe the unit to be blocked & before I strip it down I just want to make sure I don't remove anything that should be there. What does this unit & How does it work. see images on this link..http://picasaweb.google.co.uk/greggnzoe/20090711222445?authkey=Gv1sRgCISk5OPu1sCHVw#5357320535231231906