Login and Registration with PHP, MySQL and SQLite

I'm practicing to develop login and registration in a mobile app but integrated also in web app so I'm following this one: http://ift.tt/1gfNOBZ

But when running on the localhost, the output says:

{"error":true,"error_msg":"Required parameters (name, email or password) is missing!"}

this is the source code:

// json response array
$response = array("error" => FALSE);

if (isset($_POST['name']) && isset($_POST['email']) && isset($_POST['password'])) {

// receiving the post params
$name = $_POST['name'];
$email = $_POST['email'];
$password = $_POST['password'];

// check if user is already existed with the same email
if ($db->isUserExisted($email)) {
    // user already existed
    $response["error"] = TRUE;
    $response["error_msg"] = "User already existed with " . $email;
    echo json_encode($response);
} else {
    // create a new user
    $user = $db->storeUser($name, $email, $password);
    if ($user) {
        // user stored successfully
        $response["error"] = FALSE;
        $response["uid"] = $user["unique_id"];
        $response["user"]["name"] = $user["name"];
        $response["user"]["email"] = $user["email"];
        $response["user"]["created_at"] = $user["created_at"];
        $response["user"]["updated_at"] = $user["updated_at"];
        echo json_encode($response);
    } else {
        // user failed to store
        $response["error"] = TRUE;
        $response["error_msg"] = "Unknown error occurred in registration!";
        echo json_encode($response);
    }   
    }
}
else {
$response["error"] = TRUE;
$response["error_msg"] = "Required parameters (name, email or password) is missing!";
echo json_encode($response);
}
?>