hackysack on "static_html_cache questions"

Hello -

I have static_html_cache plugin active, yet my html caching doesn't appear to be working, and wanted to check if my setup is correct.

Zenphoto version 1.4.6
On the server, there is a cache_html_directory in the main zenphoto directory.

subdirectories of cache_html are:
- albums
- images
- pages
- rss
- sitemap

All of these subs are empty.
Permissions are drwsr-xr-x

Questions:
1. Are any other plugins required to be active along with static_html_cache?
2. Is my directory location and permissions correct?

Thanks for any light you shine on this.