Having a slight issue extending the product class. On each page I have an option to select a header image within the CMS. This method worked well for the Page and ProductGroup classes but wont work with the product class.

mysite/code/NicholsProduct.php:

<?php
class NicholsProduct extends Product {
   static $singular_name = 'Nichols Product Page';
   static $plural_name = 'Nichols Product Pages';
   static $db = array(
   );
   static $has_one = array(
      'HeaderImage' => 'Image'
   );
   function getCMSFields() {
      $fields = parent::getCMSFields();
      $fields->addFieldToTab('Root.Content.Main', new ImageField('HeaderImage','Header Image'),'Content');
      return $fields;
   }

}
class NicholsProduct_Controller extends Product_Controller {
   static $singular_name = ' Nichols Product Controller';
   static $plural_name = 'Nichols Product Controllers';
}

Completed a flush with no errors. Changed the behavior in the CMS to NicholsProduct now when we go to a product page we get the following error:

[User Warning] NicholsProduct_OrderItem needs to be a subclass of OrderItem
GET /florist/

Line 402 in /home/jasonmoo/public_html/nichols/ecommerce/code/control/ShoppingCart.php
Source

393    static function get_modifiers() {
394       return self::current_order()->Modifiers();
395    }
396
397    /**
398     * Get OrderItem according to product id, and coorresponding parameter filter.
399     */
400    static function get_order_item_by_buyableid($buyableID, $orderItemClassName = "OrderItem", $parameters = null ) {
401       if(!ClassInfo::is_subclass_of($orderItemClassName, "OrderItem")) {
402          user_error("$orderItemClassName needs to be a subclass of OrderItem", E_USER_WARNING);
403       }
404       $filter = self::turn_params_into_sql($parameters = null);
405       $order = self::current_order();
406       $filterString = ($filter && trim($filter) != "") ? " AND $filter" : "";
407       // NOTE: MUST HAVE THE EXACT CLASSNAME !!!!! THEREFORE INCLUDED IN WHERE PHRASE
408       return DataObject::get_one($orderItemClassName, "\"ClassName\" = '".$orderItemClassName."' AND \"OrderID\" = ".$order->ID." AND \"BuyableID\" = ".$buyableID." ". $filterString);

Can some one please point me down the correct path