Hi Tim thanks for posting!
I'm not quite sure what your problem is, although I do possibly have an alternative to try - when I want artificial lights in my renders, I always insert them inside sketchup rather than kerkythea.
On the Kerkythea toolbar inside sketchup there are buttons which create normal lights and spotlights. They're easier to place in Sketchup than in Kerky, and you can also set light power etc there (although of course they can be edited within kerky).
If you do this, make sure 'Export lights' is ticked in the export diolog.
Otherwise, perhaps check the settings for the lights you've created inside Kerky and make sure each light is enabled, and has a large enough power value to be noticable on your renders (some fiddling probably required!)
If you're interested, I'm hoping to write a basic lighting tutorial some time soon....