Possible Duplicate:
Fatal error: Call to undefined method mysqli_stmt::query()

Hey ben yukarıdaki hata mesajı alıyorum beyler, neden bulabiliriz?

$mysqli=new mysqli("localhost", "***", "***","***") or die($mysqli->connect_error);

function checklogin($username, $password){
    global $mysqli;

    $result = $mysqli->prepare("SELECT * FROM users WHERE username = ?");
    $result->bind_param("s", $username);
    $result->execute();

    if($result != false){
        $dbArray=$result->fetch_array();