I have a problem due to scopes and the form_for helper in rails 3. The routes - file looks like this:
scope \"(/:tab)\" do resources :article end >
scope \"(/:tab)\" do resources :article end
Try:
<%= form_for [:tab, @article] do |f| %> <%= f.label :title %> <%= f.text_field :title %> etc. <%end%>