Lines 572-573:
else if ( 'names' == $fields )
$select_this == 't.name';
should be
else if ( 'names' == $fields )
$select_this = 't.name';
Similarly,
Lines 582:
}
should be
} else if ( 'names' == $fields) {
$terms = $wpdb->get_col($query);
return $terms;
}