为什么这个PHP代码在指定的行上出错？

Question

第11行中的代码错误（即$type = mysqli_real_escape_string($conn, $_POST['type']);）。我在第一类设置数据库是admin，另一部分是成员。我需要让管理员去main.php，而成员到user.php ....

<?php

session_start();

if(isset($_POST['submit'])){

include 'dbh.inc.php';

$uid = mysqli_real_escape_string($conn, $_POST['uid']);
$pwd = mysqli_real_escape_string($conn, $_POST['pwd']);
$type = mysqli_real_escape_string($conn, $_POST['type']);

if (empty($uid) || empty($pwd)){
    header("Location: ../index.php?login=empty");
    exit();
} else {
    $sql = "SELECT * FROM users WHERE user_uid='$uid'";
    $result = mysqli_query($conn, $sql);
    $resultCheck = mysqli_num_rows($result);
    if ($resultCheck < 1) {
        header("Location: ../index.php?login=error");
        exit();
    } else {
        if ($row = mysqli_fetch_assoc($result)){
            $hashedPwdCheck = password_verify($pwd,$row['user_pwd']);
            if($hashedPwdCheck == false){
                header("Location: ../index.php?login=error");
                exit();
            } elseif ($hashedPwdCheck == true) {
                $_SESSION['u_id'] = $row['user_id'];
                $_SESSION['u_first'] = $row['user_first'];
                $_SESSION['u_last'] = $row['user_last'];
                $_SESSION['u_uid'] = $row['user_uid'];
                $_SESSION['type'] = $row['type'];
                if($type=='admin'){
                    header("Location: ../main.php?login=success");
                    exit();
                }elseif ($type=='member') {
                    header("Location: ../user.php?login=success");
                }   
            }
        }
    }
} else {
    header("Location: ../index.php?login=error");
    exit();
}