Both.

You should use an environment sphere. I have a free one here.

http://market.renderosity.com/mod/forumpro/showthread.php?thread_id=2746233

We have a problem with shadows through glass. You should be using IBL light, not just a single directional light.

Poser doesn't implement light passing through glass as a light source. So your shadow is 100% black. If you used "environmental" lighting, using IBL, that would not happen.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)