Hi David, I have the same problem, you are right about the lack of water getting into the washer/dryer being the problem. The Bosch washer/dryer I have is a condenser dryer which needs consistent a flow of water for the dryer to work. Do you live in an apartment block? I have found that when the Dishwasher and shower are going at the same time on a particular heavy period for others e.g. Sunday mornings the Fault you have mentioned shows up. I live in Ireland and the water pressure here is not very good which I think further compunds things. In the end (after several call outs and two replacement machines to no avail) I got a separate dryer (tricity bendix) to get around the problem.
I believe the problem to be over-engineering, the Bosch machines are too sensitive!
Hope this helps!
J Keating, April 2008