new.html.haml

= form_for @order, :url => {:action => "confirm"} do |f|
  -if @order.errors.any?
    #error_explanation
      %h2= pluralize(@order.errors.count, "error") prohibited this order from being saved:

      %ul
	      - @order.errors.full_messages.each do |msg|
	        %li= msg 

  .fields
    = f.label :user_id
    = f.number_field :user_id
  
  .fields
    = f.submit

at quick glancle, I would first try putting parantheses after form_for....like.....
form_for(@order, :url => {:action => "confirm"})

maybe?

what is the error you are getting with ur current code?