Why isn't validation kicking in and how can I make it so?

Hi,

I have a model, ec_order, which has multiple ec_line_items. You start
a "new" order through the OrderController ...

class OrderController < ApplicationController
        def new
            if logged_in?
                @user = User.find(session[:user_id])
                @ec_order = EcOrder.new
                3.times { @ec_order.ec_line_items.build }
            else
                flash[:notice] = "You must be logged in to access this
page."
                redirect_to :controller => "register", :action =>
"start"
            end
        end

        def summary
                @ec_order = EcOrder.new(params[:ec_order])
                session[:ec_order] = @ec_order
        end

...
end

Here's the ec_line_item model:

class EcLineItem < ActiveRecord::Base
        belongs_to :ec_order

        validates_numericality_of :prescription_number, :integer_only
=> true
end

In the form on the "new" view, you submit to the "summary" action.
How can I detect if the ec_line_item objects are valid or not and
reroute back to the "new" action? Thanks, - Dave

PS - If it's useful, here's the app/views/order/new.rhtml file:

===================Begin new.rhtml file=============================
<% form_for :ec_order, :url => 'summary' do |f| %>
<table>
        <tr>
                <td>Item</td>
                <td></td>
        </tr>
        <%= f.hidden_field :ship_first_name, :value =>
@user.ship_to_first_name %>
        <%= f.hidden_field :ship_last_name, :value =>
@user.ship_to_last_name %>
        <%= f.hidden_field :ship_street_address, :value =>
@user.ship_to_street %>
        <%= f.hidden_field :ship_city, :value => @user.ship_to_city %>
        <%= f.hidden_field :ship_state, :value => @user.ship_to_state
%>
        <%= f.hidden_field :ship_zip, :value => @user.ship_to_zip %>
        <%= f.hidden_field :ship_country, :value =>
@user.ship_to_country %>
        <%= f.hidden_field :email, :value => @user.email %>
        <%= f.hidden_field :phone, :value => @user.phone %>
        <tr><td>
                <table cellpadding="0" cellspacing="0" border="0">
                        <tr><td>
                                <div id="ec_line_items">
                                <%= render :partial =>
'ec_line_item', :collection => @ec_order.ec_line_items %>
                                </div>
                                <%= add_prescription_link "Add a
prescription" %>
                        </td></tr>
                </table>
        </td></tr>
        <tr><td align="center"><%= submit_tag("Submit Form") %></td></

</table>
<% end %>
========================end new.rhtml file=============================