thanks to Sam Marshall for details regarding this bug.

backup_module in backuplib.php these lines:

                foreach ($preferences->mods[$module]->instances as
$instance => $object) {
                    if (!empty($object->backup)) {
                        $status =
$onemodbackup($bf,$preferences,$instance);
                    }
                }

overwrite the $status flag and doesn't notify about anything failing - should change to something like this (untested!)
                foreach ($preferences->mods[$module]->instances as $instance => $object) {
                    if (!empty($object->backup)) {
                        $statusm = $onemodbackup($bf,$preferences,$instance);
                        if (!$statusm) {
                            notify('backup of:'.$module.'-'.$instance.' failed.');
                            $status = false;
                        }
                    }
                }

--should also check to see if backup is silent and only notify when not silent, and should log an entry to backup_log

:-)

Dan