Hi,
1. It's a HikaShop mail problem, if you have other problems with emai the best will be to create a new thread in the HikaShop question.
I will submit a patch for this email. I think that there is no payment method (or not more a existing one) for the order. So you can edit the file and replace
$payment = $paymentClass->get($data->cart->order_payment_id);
$vars['PAYMENT'] = $payment->payment_name;
unset($paymentClass);
By:
$payment = $paymentClass->get($data->cart->order_payment_id);
if(!empty($payment))
$vars['PAYMENT'] = $payment->payment_name;
unset($paymentClass);
It will check that the payment object is valid before trying to read a data from it.
2. Does the product you created is a real one ? (with a product id ?).
It think that the files does not have a product_id so there are displayed with "fake" products in order.
I will see to create a fast patch for HikaMarket and see how to create a better workaround in order to not have the same kind of troubles.
You can create files without product when you add a file during a product creation and finally, not use it (delete it before the final save). The file will stay in the database but, with no product attached.
Regards,