Hi,
Im new to Blender an Luxrender and have managed modele an interior scene for a client. Im guessing the solution to this will be simple, given my inexperience.
I have applied all my materials and lights (at least I think I have done this correctly by reading endless forums and tutorials). However when I export the scene to luxrender I get error messages and the scene is compleatly black with prescale set to 0. When I adjust prescale and burn levels I get an image but with an extreme amount of noise.
I have sunsky set and 3 interior lights.
Error message
The system has numerous assumptions, implicit and explicit,
that this transform will have no scale factors in it.
Proceed at your own risk; your image may have errors or
the system may crash as a result of this.
I havnt had sleep now for about 3 days straight!!! 
Cheers
Liam