/opt/software/ruby/gems/rails-1.2.5/lib/commands/servers/mongrel.rb:15: warning: already initialized constant OPTIONS
/opt/software/ruby/gems/rails-1.2.5/lib/commands/servers/mongrel.rb:18: undefined method `options' for :Array (NoMethodError)
when starting Mongrel or Webrick with ruby script/server are likely plugin related. You might be tempted to fire up the debugger, especially since the newly released Netbeans IDE makes debugging Rails apps almost enjoyable. However, the debugger is unlikely to help much here as the error messages don't describe the actual problem, which is missing gem dependencies of some plugin.
It's much easier and quicker to proceed as suggested in this article:
Move all plugin files from $RAILS_ROOT/vendor/plugins to a different directory. Then the web server should boot already. Then you can move the plugins back one by one and then test and see if you need any additional gems or other dependencies. Hope it helps.
rails forum: update your gems gem update --system good luck