Basically it means that your DW has a leak and the DW has sensed this automatically; accordingly, the machine won't operate with a leak. I have had this problem before, disconnected and gave the DW a good clean and a good drying out (there is a big chunk of sponge running along the base of the machine at the rear - it was saturated, so I pulled it out gave a good squeeze and dried it in outside, replaced it and connected the DW up again). The DW worked OK (but was noisier) for 8-9 months...until yesterday when I got the same fault again.
CraigK, February 2006