There seems to be some problems with the download section on the Lux site. Their website no longer guides you to the location of the correct LuxBlend python file. I have included version 0.6RC6 inside the attached BLEND file. While this may not be the latest, it does work on my Windows XP64 bit system.
Press ALT-P while your mouse cursor is over the Text window to launch the script.
ras_LuxBlend_v06RC6.blend (228 KB)