Brief
We have updated the logic in "order_items.php" script.
Description
1) When you put {order_id} tag in 'New Invoice Number Mask' settings the system starts to freeze on checkout.
2) There is a typo in 'order_items.php' that only shows up when you change the invoice mask to {order_id}.
Solution
Download the updated version of the file:
http://www.viart.com/downloads/order_items-4.zip
Further, extract the 'order_items.php' into 'includes' folder of your shop via FTP in BINARY mode replacing an existing file. Please do not forget to make a backup copy of the current file in case something goes wrong.