I've just had a little snafu installing restful_authentication in a new app, and thought I would list it here for archival purposes.
Firstly, there are messages about files not existing. My fix was to manually create lib and test/fixtures directories. (Remember, this is a brand new application.)
Secondly, There were "uninitialized constant" messages re. AuthenticatedSystem. My fix was to add "require 'authenticated_system'" to the file where AuthenticatedSystem was included.