coding error in voucher attachment path

classes\voucher.php
line 137
$attachments[1] = $upload_dir.’/voucherpdfuploads/’.$voucher_options->voucherpdf_link.’-receipt.pdf’;
actually needs to be
$attachments[1] = $upload_dir.’/voucherpdfuploads/’.$result->voucherpdf_link.’-receipt.pdf’;

Im not a PHP guy, so not sure how null value will be compared as empty string
but you might want to change line 129
$email = ($result->shipping_email != ”)?$result->shipping_email:$result->email;

to
$email = $result->email;
if (null != $result->shipping_email) {
$email = $result->shipping_email;
}