the poser 8 DVD has both mac/win installers, just like in the old days with fractal designs/MC.
the windows runtime may transfer o.k. but may have thumbs.db and possibly other crap like rsr files.
however, would recommend separate runtime in downloads folder of poser installation.
new OS X users run into overwrite issues when trying to incorporate new runtime items into main runtime.
p.s. them old PPC imacs is about as rare as hens' teeth these days.