I've had this Razer Naga for about a year now, and have used it on a now year old Razer Destructor mouse pad (it's black, and hard plastic w/ the tracking surface spray) and it's hitting invisible walls, even when I clean the mouse pad and mouse's laser regularly. I've read that a black tracking surface isn't the best for the Razer mouse lasers, and I've tried using a 8.5x11" piece of paper on top of my mouse pad, and it tracked perfectly well.
So, is it the mouse pad, or the mouse?