Language override causing cart/checkout issue

[ndunstall]

Joomla 3.9.11
Virtuemart 3.6.0   10113


Hi,

The shop I'm working on only allows for pre-registered customers to make purchases. Because of this, the customer is not required to fill out billto information etc on checkout.

I need to change the wording of "Invoice" on the pdf that is sent to client after a purchase. To do this I have gone to languages and created an override:

COM_VIRTUEMART_FILEPREFIX_INVOICE="Sales_Order_"

This should work, although now at checkout I get an error :



Invalid data entered

23 vmdebug storeCart bindChecknStore executed 24 vmdebug saveAddressInCart Var1:

1
Var2:
1
Var3:
BT
Var4:
Array
(
    [email] => XXXXX@XXXXXXX
    [first_name] =>
    [last_name] =>
    [address_1] =>
    [zip] =>
    [city] =>
)

25 vmdebug Not filled by default email




Other than a solution to this, another way of changing the title of the invoice PDF?

Any suggestions? Anything would be much appreciated.

Thanks,
N