I got a Mac to test my stuff on. I found that copying files into my Mac Poser installation folder by individual folder got very old very fast. Why on Earth the Mac OS will not allow directories to merge but insists on the new trashing the old is completely beyond me.

Macs do come with a utility called "Ditto" there is a GUI version available somewhere (Google search) that is supposed to alleviate the problem. Unfortunately I could never get it to work. To keep my sanity and probably the life expectancy of the Mac I wrote a Python script to do the job. I now have a two button click to install Poser zip files. (Browse for zip, click "OK")

I've made it freely available at http://www.philc.net/unzip.htm

If that helps, have at it, if not, no worries.