[solved] Checkout page error for some products

-- url of the page with the problem -- :
-- HikaShop version -- : 2.2.0
-- Joomla version -- : 2.5

When I add the product Lambada, all works fine, but adding the product Melba 4 posti and I click on checkout (vai alla cassa) the checkout page loses css style...
can you help me to understand why?
thanks valentina

This means that there is a fatal error on the page.
Turn on the "error reporting" option of the joomla configuration and you should then see the error message at the bottom of the page and it will tell you from where the problem is coming from.

Thanks, the uploaded images were too big.
Now it works.