problem installing plugin.

Hi I am having ruby 1.9.1 version . I am trying to install acts_as_taggable_redux plugin for tagging. When i do the following command :

ruby script/plugin install https://github.com/geemus/acts_as_taggable_redux.git

Its says

already installed: acts_as_taggable_redux (https://github.com/geemus/acts_as_taggable_redux). pass --force to reinstall

when i try doing ruby script/plugin list . Nothings returns..

rails version i am using is 2.3.1

i assume its not installed as i search for tag_cloud ruby file and not able to find it. what is the problem?