In_place_editor_field in Rails 2.0.2

I’m attempting to get an in_place_editor_field working in my index
view. I have the following:

index.html.erb

<% for profile in @profiles %>
<% div_for(profile) do %>
<% @profile = profile %>
<%= in_place_editor_field(:profile, :first_name) %>
<% end %>
<% end %>

profiles_controller.rb

def index
@profiles = Profile.find(:all)

respond_to do |format|
format.html
end
end

At one point I read something about including the following line in
the controller:

in_place_edit_for :profile, :first_name

However, that line doesn’t do much as far as I can tell. When I go to
my view, I see the text (the first name), but I cannot edit it there.
I’m a bit confused as to how this is supposed to work. Any help is
appreciated!