Hmmm, which theme were you trying to use? I think there is a problem whereby themes with spaces in their names are giving "file does not exist" error. I will fix that soon. In the meanwhile, you can rename those themes without spaces. I have now uploaded a new version of the app, which can be easily installed. It also has fixes for a few problems. No new feature as of now. I am also trying to get the app onto extras-devel.