I used to use it, but stopped when DS introduced Iray.

During the rendering process there should be a button that auto sets the light levels. Try that to see if anything appears.

If that doesn't work, make sure you have all your emitters turned on in the panel. They could be turned off or not registering as lights.

If both of those don't work, try a very simple scene. One light, a couple of simple props, and see if anything appears then.