Hi there
It maybe the rubber hose has burst from the pump. Cheap and easy to do. If the floor floods then the pump must be working to pump the water onto the floor. Take off the top of the machine. There should be 2 screws either side of the top lip inside the door recess. . Push the top backwards and it slides back and up. Access the top and side screws and the one hidden under the outer white door seal on the left hand side panel looking from the front of the machine. If the hose is not this side it will be the other side. There will be sound deadening material inside under the side panel. Just fold it back. At the bottom you will see an angled black rubber hose about 6 inches long and 1" diameter maybe more with a spring clip either end. Check it well to see if there are any splits or bulges in it. A good indicator is if you have lots of water around it and old water stains on the base panel where it's been leaking for a while. If there are bulges and it is split you may have a blocked drain outlet causing excess pressure in the hose. Check your house drain and make sure this is clear of old food debri and also the outlet pipe if the hose is bulging. If the outlet pipe is blocked you will need to give it a squeeze down it's length and a jolly good shake to get all the old food ect out of it. If it is blocked you maybe surprised by just how much muck is in it. Keep cleaning until you are sure all the old food is out of it. If it is the rubber hose burst then just unclip it and pull it off the pump outlet and drain hose outlet and replace with a Miele one. Put everything back together and it should be ok. Just make sure you turn the mains electric off first and don't touch the large silver capacitors inside as they will possibly still have a charge in them. Hope this helps. It's fiddly but easy.
Peter Jeffries Isle of Wight, May 2008