Catchable fatal error: Object of class dUser could not be converted to string in

Catchable fatal error: Object of class dUser could not be converted to string in on line 16
当运行getUserByName时，提示：Catchable fatal error: Object of class dUser could not be converted to string in on line 16的错误。不知道是哪里的问题，请大家帮忙指导。谢谢！！！

PHP code

<?phpclass dUser{    public function newpdo() {        global $dbinfo;        $dsn = "mysql:host={$dbinfo['host']};port={$dbinfo['port']};dbname={$dbinfo['dbname']}";        $pdo = new PDO($dsn, $dbinfo['user'], $dbinfo['pwd'], array(PDO::ATTR_PERSISTENT => true));        return $pdo;    }     public function getUserByName(&$info, $name) {        $dbpdo = $this->newpdo();        $sql = "SELECT * FROM `usermember` WHERE `user`=?";        $st = $dbpdo->prepare('SELECT * FROM `usermember` WHERE `user`=?');        $bRet = $st->execute(array($name));        $info = $st->fetch(PDO::FETCH_ASSOC);        return $bRet;     }}?>