Mental Ray lightingmap baking - black render (3dsmax)

Obscura

Hello, I'm having an issue with baking a lighting map with mental ray. It worked just fine earlier on an another machine, it gave perfect bakes. But now I'm working from an another pc, and I can't bake a lighting map with that. It spits out black textures with a very small, bit brighter spot on the center of the map. I tried out different exaposure/material/render settings, but nothing helps. Any idea?

Obscura

Ok I was messing with it more cause I need it working quickly. It was the exposure for some reason. I switched logarithmic exposure and now it renders what it should. This whole thing is very interesting because as I remember, I used the photographic exposure for lightmap rendering on the previous machine.