I had this same problem with my AFA350 - the engineer has just fixed it. I got this info from him - hope it helps someone else to avoid the sickening £100 call out charge!
The first light on the left flashing indicates the anti flood system has been activated. This happens when the bottom of the dishwasher (inside the mechanism, so not visible) gets filled up with water, which causes a float to activate the drainage pump to safeguard against flooding your kitchen.(which is the humming sound you will have heard when the light was flashing.)
You can fix this by tilting the dishwasher sideways about 10-15 degrees (to either side but NOT forwards or backwards) and water should drain out the side. Once all the water has drained out the dishwasher should work normally again.
The water gets into this area by a few different ways:
1. if (like me) you opened the dishwasher midway through the cycle to put something else in - this causes a pressure difference which forces some of the water down into the bottom of the machine (funny how in the handbook they said that it was OK to do that!)
2. One or more of the fittings inside the dishwasher (the thingy that sprays the water, the salt dispenser etc.) has come a little loose allowing water to get through a gap - the engineer checked these were tight with a spanner.
3. You've got a genuine leak somewhere in the system. I was told that if this is the case, then having tilted the diswasher it will work normally for perhaps a few days before getting the same fault again - in which case you will need to call out the engineer to take a look at the cause of the leak.
Hope this helps someone, somewhere!
nikki
August 2006