Have you tried uplugging and replugging your keyboard? Is there anything that could possibly be recongnized as a controller plugged in (like an adapter or something?) Does the problem persist even if you restart you computer completely?
I guess one way to check if it is the keyboard causing it would be to start pso without the keyboard plugged in, since pso only recognizes things plugged in before it is launched. If it's not the keyboard, maybe some random peripheral is being recognized as a controller and doing something funky.