I gave it a whirl (on Poser 7) and squashed some bugs as I did so.

A couple of things remain. There seems to be an inconsistency between SaveLibraryPose, which by default saves single frame poses and automatically supplies the .pz2 extension, and SaveLibraryCamera which saves animated camera settings and requires the script to supply the extension.

I've fixed the extension bug and a few others - the changes I made are marked by comments in the attached script. I can't find how to tell SaveLibraryCamera to save single frame settings - the Python methods manual says there's a parameter which I've set to zero, but I still get animated cm2s.