404. That’s an error.

The requested URL /catalog/product_compare/add/product/349/uenc/aHR0cHM6Ly93d3cuYnV5Zm9vdGJhbGxzdHVmZi5jb20vc2hvdWxkZXItcGFkcy9zaG91bGRlci1wYWQtYWNjZXNzb3JpZXMuaHRtbA,,/form_key/L8yhwKSOMtomUFbU/ was not found on this server. That’s all we know.