Redmine › Download Button

Placed the Download plugin into Redmine 2.1 and tried to start but fails with:

(2.1-working=43525) polymicro.net redmine> ruby script/rails server webrick -e production
=> Booting WEBrick
=> Rails 3.2.11 application starting in production on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require': no such file to load -- dispatcher (LoadError)
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /Library/WebServer/Documents/redmine/plugins/download/init.rb:2
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
    from /Library/WebServer/Documents/redmine/lib/redmine/plugin.rb:130:in `load'
    from /Library/WebServer/Documents/redmine/lib/redmine/plugin.rb:121:in `each'
    from /Library/WebServer/Documents/redmine/lib/redmine/plugin.rb:121:in `load'
    from /Library/WebServer/Documents/redmine/config/initializers/30-redmine.rb:13
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:245:in `load'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:245:in `load'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /opt/local/lib/ruby/gems/1.8/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:245:in `load'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/engine.rb:588
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/engine.rb:587:in `each'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/engine.rb:587
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `instance_exec'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `run'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/initializable.rb:55:in `run_initializers'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `each'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `run_initializers'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/application.rb:136:in `initialize!'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/railtie/configurable.rb:30:in `send'
    from /opt/local/lib/ruby/gems/1.8/gems/railties-3.2.11/lib/rails/railtie/configurable.rb:30:in `method_missing'
    from /Library/WebServer/Documents/redmine/config/environment.rb:14
    from /Library/WebServer/Documents/redmine/config.ru:3:in `require'
    from /Library/WebServer/Documents/redmine/config.ru:3
    from /opt/local/lib/ruby/gems/1.8/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
    from /opt/local/lib/ruby/gems/1.8/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
    from /Library/WebServer/Documents/redmine/config.ru:0:in `new'
    from /Library/WebServer/Documents/redmine/config.ru:0