Quote - > Quote - Note that in addition to the default shader in the package there is also the Post-240 shader using Sub Surface Scattering.

Is that the VSS shaders I see in the MAT pose folder?  Are those meant to be used with SSS checked? 

Yes.See page 393 of the Poser Reference manual:

Materials that use subsurface scattering will not render properly if this option is disabled.

Quote - What lights do they not work with?

There were some issues in IDL scenes that use as a main light dource indirect light from a surface with a high ambient value (miming a diffuse screen as used in a photographic studio) and a specular-only spotlight for the highlights. There is nothing wrong with the combination in itself, except that the conventional shader gave better results in those cases. There has been late work going on to solve the issues. There is no good or bad in this case. Just check and see how shaders work out for you in your scene. The readme .pdf gives guidance on how you can tweak the Post-240 shader to your needs.