406 Not Acceptable error when trying to print

gistfile1.txt

Started GET "/admin/orders/R620580058.pdf?template=invoice" for 10.10.10.11 at 2012-06-18 12:53:27 -0400
Processing by Spree::Admin::OrdersController#show as PDF
  Parameters: {"template"=>"invoice", "id"=>"R620580058"}
  Spree::User Load (4.3ms)  SELECT `spree_users`.* FROM `spree_users` WHERE `spree_users`.`id` = 351 LIMIT 1
  Spree::Role Load (4.8ms)  SELECT `spree_roles`.* FROM `spree_roles` INNER JOIN `spree_roles_users` ON `spree_roles`.`id` = `spree_roles_users`.`rol
e_id` WHERE `spree_roles_users`.`user_id` = 351
  Spree::Order Load (3.8ms)  SELECT `spree_orders`.* FROM `spree_orders` WHERE `spree_orders`.`number` = 'R620580058' LIMIT 1
  Spree::Adjustment Load (4.0ms)  SELECT `spree_adjustments`.* FROM `spree_adjustments` WHERE `spree_adjustments`.`adjustable_type` = 'Spree::Order'
AND `spree_adjustments`.`adjustable_id` IN (378) ORDER BY created_at ASC
  Spree::Order Load (6.5ms)  SELECT `spree_orders`.* FROM `spree_orders` WHERE `spree_orders`.`user_id` = 351 AND `spree_orders`.`completed_at` IS NU
LL ORDER BY created_at ASC LIMIT 1
Completed 406 Not Acceptable in 52ms (ActiveRecord: 23.4ms)