Same problem. brute force is the key and dont be scared.
lift the wiper from the windscreen, grab the bit where the nut was in one hand and the bit that is now sticking in the air with the other now its kinda like trying to rub your belly while tapping your head..... move first hand horizontally left to right and then second one on bit in the air up and down. give it some welly and they will come away eventually.
ian
August 2007