If you have three different lights, and they all have shadows turned on, you'll have three different shadows because the lights are in different places in the scene ;).

Since you used two lights, the infinite is going to shadow everything in the scene. The shadow on the wall is your spotlight. The two on the ground are the shadow from the plane and the figure. I don't see anything that's not supposed to be there.

IDL will lighten shadows in areas where the direction of two different lights intersect. This happens in real life as well. It also depends on the relative strengths of the two lights, their direction, and how close they are to the objects.

Laurie