Hi,
The issue comes from old code you have in the preload override of the email order creation notification.
So you need to go in the menu System>Emails of HikaShop to sort that out.
The simplest is to just delete the customization of the preload from the listing there. That will fix the problem since the faulty code is not in the current default version of the preload.
However, if you have this override, it means you had customized it in the past. So you would lose that customization if you had any.
So first, I would recommend checking what you have in there.
And if there is code modification you want to preserve, you need to copy/paste it somewhere else so that you can reapply it to the current default version of the preload, after you've deleted the faulty old override.