Frigidaire Dishwasher?

I have a Frigidaire Dishwasher that I installed myself a year ago. Worked alright for a while, until the drain hose had gotten clogged a while back. Called in a plumber and it worked like a charm. Now one day I came home to find the lower spray arm was melted, and judging by it there were some flames inside. I replaced the arm and a gasket on the bottom of the door with some parts I ordered from sears. I'm still getting an error code UO.