Thanks! I actually did try those things but it still wouldn't budge. In the end, I had to drive a chisel through the filter and then pound on the ends of the chilsel for a full turn before the filter turned easily in my hand. Obviously, the mechanic at the Toyota dealership overtightened the filter or perhaps neglected to put a thin film of oil on the gasket before installing it. My new filter spun on easily and I made sure not to overtighten it. Before re-installing the skid plate I checked to make sure there were no leaks with the engine running. Everything looks ok and next time I probably won't have to remove the skid plate.