Well I'm not familiar with Macs but even free stuff with incorrect paths have the runtime structure in them, the problem is they have a name in front of the runtime which is why it doesn't auto install!

Anyway, once unzipped to your temp folder, open up the runtime folder and in there you'll find other folders for "character" "pose" "texture" "geometry" there may be others depending on what the item is.
To load these manually you'll need to open each folder [character, pose, texture, gemoetry] and do a cut or copy and paste to the corresponding folders inside your Poser runtime.
That's how it works in windows anyway, as I said I'm not familiar with macs!

Injustice will be avenged.
Cofiwch Dryweryn.