Only check for existing contacts if an email address is present

program/steps/addressbook/save.inc

@@ -162,7 +162,7 @@ else {
   // show notice if existing contacts with same e-mail are found
   $existing = false;
   foreach ($CONTACTS->get_col_values('email', $a_record, true) as $email) {
-      if (($res = $CONTACTS->search('email', $email, false, false, true)) && $res->count) {
+      if ($email && ($res = $CONTACTS->search('email', $email, false, false, true)) && $res->count) {
           $OUTPUT->show_message('contactexists', 'notice', null, false);
           break;
       }