Yes, the light manager uses the ABT. If the problem only occurs with small light ranges, then no surface is in the range of the light. At least one vertex must be inside the light sphere for seeing any effect of the light. You can see the vertex positions when pressing F11 twice.
If you are unsure about which walls are in the range of your light, I've uploaded a light test shader here:
http://opserver.de/down/lightcount.fxSet this shader to the wall material - mat_shaded - and you'll see the number of lights on any surface in its color. 0 lights are black, one light is blue, 2 lights green and so on.
If you can't find the reason of the problem this way, you can send the project to support. We'll check.