Usando Paperclip 3.0.1 en rieles 3.2.2 obtuve este error:

<code>**Paperclip::AdapterRegistry::NoHandlerError** 
(No handler found for "2009-11-29-133527.jpg"):
</code>

En mi modelo tengo:

<code>class Product < ActiveRecord::Base
    ...
    has_many :assets 
    accepts_nested_attributes_for :assets
 end

 class Asset < ActiveRecord::Base
     belongs_to :product
     has_attached_file :image,
               :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
               :url => "/system/:attachment/:id/:style/:filename", 
               :styles => { :medium => "300x300>", :thumb => "100x100>" }
  end
</code>

La excepción se plantea en:

<code>def create
     **@product = Product.new params[:product]**
     ...
end
</code>

con params:

<code>{...,
 "product"=>{"title"=>"wibble1", 
             **"assets_attributes"=>{"0"=>{"image"=>"2009-11-29-133527.jpg"}
                                  },** 
             "description"=>"Who is wibble...", 
             "price"=>"23.45"
            }, 
             "commit"=>"Create Product", 
             ...}
</code>

Alguien sabe que esta pasando?