Some component is leaking water. It collects in the bottom panel and activates a polystyrene float which rises and sets a microswitch which will stop the programme with a flashing Start light. I guess that after a week the water has evaporated and it will allow you to reset.
Th first time this happened to me is when one of the crappy hose clamps fitted at the factory fell off. Check if this is so, and if so, replace the cheap and nasty clamp with a decent Jubilee clip which you can tighten with a screwdriver or spanner.
The second time this happened is when the seals on the wash pump failed, and water leaking from this causes the same problem. Check for signs of leakage on the pump (it's on the bottom right hand side at the back)
This is why I'm currently trying to source a replacement pump...
Hope this helps!
barry
October 2004