Light Groups in Luxrender

I am trying to assign my lights to light groups so I can adjust them. However, I have a problem:
When I assign an emission material to a mesh, I can add it to a light group that I have created. When I render and am in the luxrender external window, that light group shows up. However, it is not rendering any light for that object. Is it something wrong with the material? I made sure that the gain/importance/efficacy were up.

Also, when I drag, the “Gain” slider in Luxrender for a normal lamp in a lightgroup (and for ‘default’), it changes only for a second, then returns to what it was before.

2nd problem resolved, works only for 2 or more light groups. (It’s relative)

It actually is absolute, it just appears to be relative because Lux auto-exposes by default:

For the mesh with the emission material, are you sure it is not being drowned out by a much brighter light, like the sun? Try turning off render visibility in the outliner for your other lamps and then render. See what you get. Also, mesh emitters in Lux only shine in the direction that the normal faces, so double-check the direction there.

Mesh is only emitting object in scene, normals are correct.

Hrmmph. Can you post a blend file?

Wow, uhhh, works all of a sudden, didn’t change anything. This thread is obviously useless.