I looked at the compression script. One thing I noticed is there is no import statement for the Poser methods. This is most likely the problem since you have Poser installed on the D: drive. Try this:

Open the script in a text editor
Near the top of the script you'll see two import statements -

import gzip
import string

Add a third import statement -

import poser

Save the script under a new name with the .py extention and try it.

This should do the trick. If not let me know.