Message repeated twice

-- url of the page with the problem -- : dmware.com/nw14/it/shop/checkout
-- HikaShop version -- : Essential
-- Joomla version -- : 3.x
-- PHP version -- : x.x.x
-- Browser(s) name and version -- : XXXXX x.x.x


I don't get why once I add to the cart a product I get this message repeated twice:

www.diigo.com/item/image/2gyji/ops0

Hi,
Note that you'll have to configure a payment method, so can you create and configure a payment method through "Hikashop->System->Payment methods" and test it again ?
Thanks.