function ProcessGatewayResult(..) breaks the order processing if no e-mail
address was given during submitting order.

This piece of code tries to get e-mail address from the order, if e-mail is not
provided it returns an error string that is NOWHERE displayed:

    // Get the email address
    $billing = $order_obj->get_billing();
    $tmp = $billing->get_email();
    if( $tmp )
      {
	$email_addr = $tmp;
      }
    if( !$email_addr )
      {
return $this->Lang('error_noemailaddress'); <---------------- breaks order
updating
      }

Order processing is finished at this place without any debug notice. Order
status is not updated, e-mails are not sent out.

--------------------------------------
Possible solutions:
-------------------------------------
1. Make e-mail address mandatory in order form.
2. Get e-mail address from FEU-account if it was not provided during order
submit.