I fornd this answer on another chat room:
This error means that pressure in drain system is grater than expected. It could occur for two reasons. Most likely, your drain hose is quite long and placed as to make water to suspend in it after draining cycle. Another reason is too much foam. I had the first one. After hanging up the hose above the level of draining hole the problem disappeared. It is nothing dangerous anyway.
Jixi, June 2009
