Ockham, there was nothing whatsoever wrong with your OneRender script! =o.

I found out why some of my files wouldn't render (got an 'Invalid scene object' error). I think they were too "far down" in directory!

After I've tested my scene by first, adding one item at a time and then Pythonize it. And second, deleting one item at a time and Pythonizing. Still errrors.
Then I moved the whole bunch of files "higher up" in directories. Same files no Python errors!
Strange huh. It's as if it was too far from the Python script somehow.

Just wanted ya' to know. :o)