Impossible to edit a shelve

[lduby]

Started GET "/profiles/3/shelves/8/edit" for 80.12.110.204 at 2012-08-22 11:49:53 +0200
Processing by ShelvesController#edit as HTML
Parameters: {"name_prefix"=>"profile_", "profile_id"=>"3", "id"=>"8"}
Shelf Load (0.5ms) SELECT "shelves".* FROM "shelves" WHERE "shelves"."id" = ? LIMIT 1 [["id", "8"]]
Rendered shelves/_form.html.haml (13.4ms)
Rendered shelves/edit.html.haml within layouts/application (21.2ms)
Completed 500 Internal Server Error in 53ms

ActionView::Template::Error (undefined method shelves' for nil:NilClass): 1: = form_for([@profile, @profile.shelves.build]) do |f| 2: %dl.dl-horizontal 3: .field 4: %dt= f.label :name app/views/shelves/_form.html.haml:1:in_app_views_shelves__form_html_haml___557546682_89494620'
app/views/shelves/edit.html.haml:3:in `_app_views_shelves_edit_html_haml__446850792_90477330'

Rendered /home/laet/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.3/lib/action_dispatch/middleware/templates/rescues/_trace.erb (19.2ms)
Rendered /home/laet/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.3/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (4.9ms)
Rendered /home/laet/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.3/lib/action_dispatch/middleware/templates/rescues/template_error.erb within rescues/layout (53.8ms)