Please help getting error in fields_for

Hi,
I am using the fields_for and am getting a problem of

"undefined local variable or method `organisation' for
#<#<Class:0x4775534>:0x477550c>"

my person model is as

class Person < ActiveRecord::Base
  has_and_belongs_to_many :organisations

My Organisation model is as
class Organisation < ActiveRecord::Base
  has_and_belongs_to_many :people

Please help me with this. I was following the railscasts complex forms2
74

This is the code for form to create a new person and simultaneously
create an organisation for that person.

<%form_for :person,:url=>{:action =>"submit_tag"} do |p|%>
  <%=submit_tag 'CREATE INDIVIDUAL', :name=>"submit"%>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  <%=submit_tag 'SEARCH INDIVIDUAL', :name=>"submit"%>
  <%=render :partial=>'person_fields' , :locals=>{:p=>p}%>

  <%=submit_tag 'CREATE INDIVIDUAL', :name=>"submit"%>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  <%=submit_tag 'SEARCH INDIVIDUAL', :name=>"submit"%>

<%fields_for "person[organisation_attributes][]",organisation do

org_form|%>

<div id = "organisation"><%=render
:partial=>'organisation_with_index_nil_for_person',:collection=>@person.organisations,:locals=>{:org_form=>org_form}%>
</div>
<b><%=link_to_function "Add an Organisation" do |page|
page.insert_html
:bottom,:organisation,:partial=>'organisation/organisation_with_index_nil_for_person',:object=>Organisation.new
end%></b>
<%end%>
<%end%>

Please help me
Thanks
Regards
Anks.