My modifications above are for the store-end, not for the admin while the error message you specified occurs from the admin end.
In admin/controller/sale/order.php file,
find:
add
above:
Code: Select all
$this->data['text_customer_id'] = $this->language->get('text_customer_id');
$this->data['text_guest'] = $this->language->get('text_guest');
Then, find:
add after:
Code: Select all
'customer_id' => $order_info['customer_id'],
And assure not to have it twice in the array to avoid confusion.
In admin/language/english/sale/order.php file,
find:
add after:
Code: Select all
$_['text_customer_id'] = 'Customer ID: ';
$_['text_guest'] = 'Guest';
In admin/view/template/sale/order_invoice.tpl file,
find:
Code: Select all
<tr>
<td><b><?php echo $text_order_id; ?></b></td>
<td><?php echo $order['order_id']; ?></td>
</tr>
add after:
Code: Select all
<tr>
<td><b><?php echo $text_customer_id; ?></b></td>
<td><?php echo (!empty($order['customer_id'])) ? (int)$order['customer_id'] : $text_guest; ?></td>
</tr>
And assure not to have the customer_id twice from that template file to avoid confusion.