Did you put LuxBlend_0.6.py where I pointed you?

C:/Documents and Settings/MyName/Datos de programa/Blender Foundation/Blender/.blenderscripts

(use back slash in the direction, I cant use it so I typed "/")

I repeat, My Windows is spanish, I don't know how "Datos de programa" is named in english Windows

After doing it close Blender and reopen, let's see if it works

and you don't need to add ambient occlussion to the model Luxrender do true phisical light render