Hello Adria,
It's quite difficult to say what can be the cause of such problem with such small piece of information. If you give us a little more information about problem you have, for example full url to the cart where you use it, then we can try to check this problem for you.
Thanks,
ViArt Support Team
I have been using the free version of you site and it has been working great until today - now when I submit an order and use the PayPal payment gateway (which was working just fine) I get an error:
Such Order doesn't exist.
The page stops with www.mydomain.it/payment.php?#user_detail
Any ideas why this happend. I didn't change it at all. IS it maybe Paypal problems?