I don't know. The way this plugin is done seems a bit shady to me.
You can download the version from WP.org. But, while using that version, you get this message:
You can add only 10 pages.
If you want unlimited number of pages download latest version here: http://pageflipgallery.com/download/
So, you download that version, of course. Except, this new version is not licensed under the GPL.
This would totally not fly with the themes directory. I'm not sure if WP.org should support this plugin when the page it links to supports non-GPL versions. That's part of the reason why 200 – 300 WP themes were removed recently from the directory.