EDIT:  sorry, I didn't see that you were wanting to save files for future use instead of just saving hard drive storage.

Personally what I would do in your place is use an external hard drive and compress the files inside Poser and not do the zipping thing.

Last year I reformatted my hard drive and I spent 12 hours burning CDs so that I wouldn't lose my poser runtimes or any other important data.   I figured that the reformat was going to be a breeze. How wrong I was.   Almost every single CD that I burned had some kind of "cannot inflate" error for some files and as you know with a Poser it's important to have ALL of the files, not just some. Rather than wasting my time trying to figure out what files unzipped and what didn't, I ended up reinstalling my runtimes from scratch.  

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi