I got this error when I have to upgrade one old project from rails 1.2.5 to rails 2.1 (the problem is not in rails)

ActionController::MethodNotAllowed

Only get, head, post, put, and delete requests are allowed.

The exception:

ActionController::MethodNotAllowed (Only get, head, post, put, and delete requests are allowed.):
    /usr/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/routing/recognition_optimisation.rb:65:in `recognize_path'
    /usr/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/routing/route_set.rb:384:in `recognize'

I got this error only when I access URL’s with param like

http://127.0.0.1:3000/dod/images/show_big_image/1639

I found that the problem was in the :id because without the :id the method was called correctly

This means that there is something with the routes.

Not working routes.rb: ….

  map.connect '', :controller => 'auth'

  # Install the default route as the lowest priority.
  map.connect ':controller/:action/:id'
  map.connect ':controller/:action/:sort_key/:sort_order'

it will work if you swap the last two lines….

  map.connect '', :controller => 'auth'

  # Install the default route as the lowest priority.
  map.connect ':controller/:action/:sort_key/:sort_order'
  map.connect ':controller/:action/:id'

It seems that it does reading the comments in the routes.rb is usefull. There is written:

# Install the default route as the lowest priority.

This error also occurs if you haven't restart your webserver. I know that there is no need to restart it but its true, try restarting and check.