Ruby on Rails : "No route matches controller"

I am new to RoR, but I have been struggling with a mysterious error for days.
I am using a standard installation approach on a clean ubuntu system

I created a very simple application, just reading from a mysql table called dogs.
The application was totally generated with scaffold.

rails server -p 3001   #Starts server


When I run, I get the error "No route matches controller"
   http://localhost:3001/dogs  

If I remove all the link_to cells, the application runs and returns data.

If I put back just one line "    <td><%= link_to 'Show', dog %></td>",
 I still get the error complaining about the  ":action=>"destroy" route.


== scaffold ==

rails g scaffold dog dog_id:integer color:string gender:string dog_name:string --skip-migration


===========Generated Source Code=============

<% @dogs.each do |dog| %>
  <tr>
    <td><%= dog.dog_id %></td>
    <td><%= dog.color %></td>
    <td><%= dog.gender %></td>
    <td><%= dog.dog_name %></td>
    <td><%= link_to 'Show', dog %></td>
    <td><%= link_to 'Edit', edit_dog_path(dog) %></td>
    <td><%= link_to 'Destroy', dog, :confirm => 'Are you sure?', :method => :delete %></td>
  </tr>
<% end %>

========= ERROR ===========
## No route matches controller ############
Showing /home/ruby/hub2/app/views/dogs/index.html.erb where line #20 raised:
No route matches {:controller=>"dogs", :action=>"destroy", :id=>#<Dog dog_id: 1, color: "Golden", gender: "Female", dog_name: "Daisy">}

Extracted source (around line #20):

17:     <td><%= dog.color %></td>
18:     <td><%= dog.gender %></td>
19:     <td><%= dog.dog_name %></td>
20:     <td><%= link_to 'Show', dog %></td>
21:     <td><%= link_to 'Edit', edit_dog_path(dog) %></td>
22:     <td><%= link_to 'Destroy', dog, :confirm => 'Are you sure?', :method => :delete %></td>
23:   </tr>

========== routes.rb   ==============
Hub2::Application.routes.draw do
  resources :dogs
end


========= rake routes ============
root@ubu-bob:/home/ruby/hub2# rake routes
(in /home/ruby/hub2)
    dogs GET    /dogs(.:format)          {:controller=>"dogs", :action=>"index"}
    dogs POST   /dogs(.:format)          {:controller=>"dogs", :action=>"create"}
 new_dog GET    /dogs/new(.:format)      {:controller=>"dogs", :action=>"new"}
edit_dog GET    /dogs/:id/edit(.:format) {:controller=>"dogs", :action=>"edit"}
     dog GET    /dogs/:id(.:format)      {:controller=>"dogs", :action=>"show"}
     dog PUT    /dogs/:id(.:format)      {:controller=>"dogs", :action=>"update"}
     dog DELETE /dogs/:id(.:format)      {:controller=>"dogs", :action=>"destroy"}


=== Installation ===
 I followed these instructions on a brand new and fully updated version of ubuntu 10.04

 http://castilho.biz/blog/2010/05/08/how-to-install-ruby-on-rails-on-ubuntu-10-04-lucid-lynx/
 How to install Ruby on Rails on Ubuntu 10.04 Lucid Lynx
    Follow these steps to have a fresh installation of Ruby on Rails in Ubuntu 10.04:
   
  sudo su
  apt-get -y install build-essential
  apt-get -y install ruby rdoc libopenssl-ruby
  wget http://production.cf.rubygems.org/rubygems/rubygems-1.3.7.tgz
  tar zxvf rubygems-1.3.7.tgz
  cd rubygems-1.3.7
  ruby setup.rb
  ln -s /usr/bin/gem1.8 /usr/local/bin/gem
  gem install rails  ;# (takes awhile with no output.. )
   
#Installing MySQL gem:
   
  apt-get -y install ruby-dev libmysql-ruby libmysqlclient-dev
  gem install mysql

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