404. That’s an error.

The requested URL /catalog/product_compare/add/product/1296/uenc/aHR0cHM6Ly9zaW1wbGEuYXo6ODA4MC9ldi1oZXl2YW5sYXJpL2VsZWt0cmlrLWVsZWt0cm9uaWthLmh0bWw,/form_key/xLG6vy1Cg5iZ2e4V/ was not found on this server. That’s all we know.