Error message

• Notice: Undefined index: default_product in commerce_product_urls_form_alter() (line 63 of /home/autoalati/public_html/sites/all/modules/commerce_product_urls/commerce_product_urls.module).
• Notice: Trying to get property of non-object in commerce_product_urls_form_alter() (line 63 of /home/autoalati/public_html/sites/all/modules/commerce_product_urls/commerce_product_urls.module).