Model method disappear after first page request

I can't figure out why model methods disappear after the first page
request? If I restart Webrick, I can load the page once, without
error, but refresh the page, and I keep getting method missing
errors. My code is extremely simple:

class LineItem < ActiveRecord::Base
  belongs_to :order
end

class Order < ActiveRecord::Base
  has_many :line_items
end

--> index.rhtml
<%= @line_item.order.id %>

Error is like method "order" missing for <LineItem:#29932...

This is in development mode, Rails 1.2, Windows 2000, Webrick

Help!

What code do you have in your controller?

M<><

Nothing, except for the scaffold_resource inserted code, like
respond_to html...

It's in the index action, and I'm using the REST architecture. My
index.rhtml source is like:
<% for acc in @user.accounts %>
  <% for line_item in acc.line_items %>
    <%= line_item.order.id %>
  <% end %>
<% end %>

Note: You can pull back the line items by account, as each LineItem
has an AccountID