Error 400 Ambiguous URI path separator

HTTP ERROR 400 Ambiguous URI path separator

URI:	http://raago.no/404/index.php%3Fproduct_configuration_product_id=293&route=product%2Fproduct_configurations?product_configuration_product_id=293&route=product%2Fproduct_configurations
STATUS:	400
MESSAGE:	Ambiguous URI path separator