I am using the redmine of ruby and try to install the plugin meetings and face some issue. please help me

My ruby and redmine installation are as follows.

Environment:
  Redmine version                3.3.1.stable
  Ruby version                   2.1.5-p273 (2014-11-13) [x86_64-linux]
  Rails version                  4.2.7.1
  Environment                    development
  Database adapter               Mysql2

AND I AM USING THIS PLUGIN http://ift.tt/2jymNoX AND FACE THE FOLLOWING ISSUE WHEN RUN THE RAKE MIGRATE.

An error occurred while loading the routes definition of meetings plugin (/var/www/html/rubyproject/redmine/plugins/meetings/config/routes.rb): Invalid route name, already in use: 'new_meeting'

I AM NEW TO RUBY..