runner_mail problem

Hi,
phprunner enterprise 10.91 build 41974 x64
email with attacments

$fileArray = my_json_decode($values["allegemail"]);
$attachments = array();
$msg = "";
foreach($fileArray as $f)
{
$attachments[] = array("path" => $f["name"]);
}
when i use runner_mail(array('from' => $from,'to' => $email,'bcc' => $ccn,'subject' => $subject,'body' => $body,'attachments' => $attachments));
if there are no attachments "(null)" is added at the bottom of the email body
i also try runner_mail(array('from' => $from,'to' => $email,'bcc' => $ccn,'subject' => $subject,'body' => $body));
and "(null)" is added at the bottom of the email body

How can I avoid having "(null)" at the bottom of the email?
Thanks
Fabio