Adding an Arnold Light turns the scene black

[AnimationSB]

I have this scene set up correctly with some lights. Notice I have 1 arnold light on one fixture. It renders okay.

But the moment I add an Arnold light to the scene, the entire scene renders totally black.

This can be whether I:

• clone an instance of the current light
• copy the current light
• create and place a new Arnold light

Anytime I add 1 more light, it starts rendering totally black

[BenBisares]

Would it be possible to attach an archive of this scene or if the data is sensitive the same scene but with objects replaced by something like a box?

I'd like to take a look at what's happening.