Here is a picture of what I am seeing. In this, the yellow portions are from the lava object which I have selected as my AG object (in this case it is a very thin vertex object). The remainder is the terrain. Even though the AG brightness is turned up to 200, there is almost no light illuminating the terrain. There is some, but very very little.

The AG settings are as follows: brightness 200, range 400, falloff 45, cast shadows on, color Light Color, origin Vertex,
fidelity 5000, standoff 0.25, min distance 0.25.