I had the same problem, it was solved by getting the 66.81 nVidia drivers. But the shader never worked for me, it did not “suddenly stop working”, so this might not help you…
There doesn’t seem to be a 66.81 driver anywhere on the nVidia website. The 66.93 one I found didn’t solve it.
The registered developer section didn’t have that driver version either.
I know this shader worked at one point or another a few months back, unfortunately I can’t remember what driver version I was using back then.
I suppose I’m going to try some of the recent drivers from the past and see if i can get it working again…if you happen to have an installer for that driver version do you think you could pass it over to me?