Just a note many older Themes and Extensions/Addons can and will break with the introduction of Firefox 29 (Australis) In most cases they cannot be updated by bumping the version in the XPI.
Australis Guide for Normal People
I have no idea what XPI is so woud have to do research on that, but probably will just go straight to Pale Moon.
You save the extension to your pc then right click on it and “open with” notepad. You then change the version number if the creator of the app did not come up with an update. Now they are saying it won’t work.
That’s typical with any of the major updates to FF.