normal maping tutorial problem

Hi I am in the middle of the normal maping tutorial from the resource page and I ran into a snag when I got to the part of implementing the Nvidia plug-in. It downloaded and installed alreat but when I go into Photoshop and try to complete the step the tool is not located under filter like the tutorial's or under any of the dropdown boxes.

I am running vista and am using photoshop cs4.

Does anyone know why it wouldn't show up under filter.