gistfile1.txt

Am getting the following error:
Modul(#36555780) expected, got String(#21132310)

After doing a lot of research on the net, i found that i need to pass
on the id field somehow, but i dont really know how to do it.

Following is the model:
---------------------------------
class Modul < ActiveRecord::Base
 belongs_to :modulable, :polymorphic => true
end

class Chapter < ActiveRecord::Base
 has_many :moduls, :as => :modulable
 accepts_nested_attributes_for :moduls
end

New Page:
----------------
<h1>New chapter</h1>

<% form_for @chapter do |chapter_form| %>
 <%= chapter_form.error_messages %>

         <% chapter_form.fields_for :moduls do |modul_form| %>
                 <p>
                   <%= modul_form.label :name %><br />
                   <%= modul_form.text_field :name %>
                 </p>
                 <p>
                   <%= modul_form.label :alias %><br />
                   <%= modul_form.text_field :alias %>
                 </p>
                 <p>
                   <%= modul_form.label :description %><br />
                   <%= modul_form.text_field :description %>
                 </p>
                 <p>
                   <%= modul_form.label :level %><br />
                   <%= modul_form.select :level, %w{ nil 0 1 2 3 } %><br />
                 </p>
                 <p>
                   <%= modul_form.label :parent %><br />
                   <%= modul_form.text_field :parent %>
                 </p>
         <% end %>
    <p>
   <%= chapter_form.label :chapter_type %><br />
   <%=
       #@decodes = Decode.find(:all, :conditions => {:name =>
"Chapter_Type", :is_active => 1 })
       @decodes = Decode.all(:conditions => {:name =>
"Chapter_Type", :is_active => 1 })
       chapter_form.collection_select :chapter_type,
@decodes, :id, :display_value, :prompt => 'Select chapter
type'
       %>
 </p>

 <p>
   <%= chapter_form.submit 'Create' %>
 </p>
<% end %>

<%= link_to 'Back', chapters_path %>


Controller:
---------------
class ChaptersController < ApplicationController

def create
    @chapter = Chapter.new(params[:chapter])

   respond_to do |format|
     if @chapter.save
       flash[:notice] = 'Chapter was successfully created.'
       format.html { redirect_to(@chapter) }
       format.xml  { render :xml => @chapter, :status
=> :created, :location => @chapter }
     else
       format.html { render :action => "new" }
       format.xml  { render :xml => @chapter.errors, :status
=> :unprocessable_entity }
     end
   end
 end

end

Logs:
=====
Processing ChaptersController#create (for 127.0.0.1 at 2009-06-19 21:02:28) [POST]
  Parameters: {"commit"=>"Create", "chapter"=>{"chapter_type"=>"1", "moduls_attributes"=>{"0"=>{"name"=>"t", "level"=>"1", "description"=>"t", "alias"=>"t", "parent"=>"1"}}}, "action"=>"create", "authenticity_token"=>"EV3yhF3gFxf3a6hHwfvfQ15zCFFYx0CXs45IESt+nNU=", "controller"=>"chapters"}
  Chapter Columns (15.0ms)   SHOW FIELDS FROM `chapters`
  Modul Columns (0.0ms)   SHOW FIELDS FROM `moduls`

ActiveRecord::AssociationTypeMismatch (Modul(#37776460) expected, got String(#21132310)):
  app/controllers/chapters_controller.rb:47:in `new'



Does anyone have an idea about the problem?

Thanks in advance,
Prats