error in rails in locator.rb:91:in `add’: wrong number of arguments (3 for 1) (ArgumentError)

When I tried to start my rails-app this morning on my new server, I got:

** Starting Rails with development environment…
Exiting
/usr/lib/ruby/gems/1.8/gems/rails-2.1.0/lib/rails/plugin/locator.rb:91:in `add’: wrong number of arguments (3 for 1) (ArgumentError)

That seems to be a problem with an old install of rubygems on my Ubuntu-machine. Didn’t know that. It lives inside /usr/lib/ruby while the new versions normally reside at /usr/local/lib/site_ruby

Solution:

Delete /usr/lib/ruby/1.8/rubygems.rb and /usr/lib/ruby/1.8/rubygems (the latter is a directory)

Thanks to Stephan for this article:

http://www.arkanis-development.de/weblog/2008/9/19/locatorrb:91:in-%60add:-wrong-number-of-arguments