It only works on 4.1.
Your issue might be that you need to get into the .them folder and take out the individual themes. If you ssh into your themes folder, it'll look something like this.
/var/stash/themes/retina signal/(5 other themes)
The theme, when downloaded is like having 5 theme folders inside of a theme folder. So those 5 need to be taken out so they can be activated individually.