Hi,
As you can read in the error message ; you have a PHP error in the "modified" version of the order creation notification email.
It means that you have modified that email and that your modification have an error.
The easier will be to remove your customization by deleting the override in your HikaShop backend.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.