I remember reading a Tom Swift novel when I was a kid. His plane crashed and wrecked his radio. He rebuilt it using a slab of wood for a "mother board", using conductive pencil lines in place of copper traces. Pretty fanciful? yes
Wood is a good enough insulator (when dry) but I wonder if what you used to draw the component outlines and connections is conductive.
I'd also make sure you have a good air gap between the power resistors and the board.