I found these error codes for the hotpoint fdw80
AL01 - Anti flood switch operated
AL02 - Valve or connections
AL03 - Time out - drain
AL04 - Thermistor (module)
AL05 - Circulation pump
AL06 - Time out - fill
AL07 - Not used
AL08 - Time out - heat
AL09 - Software recogntion error
AL10 - Heating circuit
AL99 - Communications error - connectors, cables etc.
H20 - Time out - fill (taps)
Now looking at AL10 error. Most often it is the heater element which is not effective due to scale formation. Make a solution of white vinegar and water (50:50) pour it onto the base of the dishwasher. Leave overnight and run dishwasher as normal. Somehow the vineger has to reach the heating element which is an inline heater. I am assuming normally you would use the hotwater connection from the kitchen tap.
If this does not help - depends how soon into the cycle you get the error you will have to replace the heater. I think it would look like this