Assalamualaikum,
Mas mau tanya, saya membuat form login multi user,pas saya coba login ga bisa masuk malah eror password salah, padahal password udah benar, kira-kira script saya salah pada bagian mana? mohon pencerahan saya ingin belajar php.
ini script loginnya :

<?php
	session_start();

	require_once('config/koneksi.php');

	$login = clean($_POST['login']);
	$password = clean($_POST['password']);
	$user_type = clean($_POST['user']);

	$errmsg_arr = array();
	$errflag = false;
	
	if($login == '' && $password == '' && $user_type == '') {
		header("location: index.php");
		exit();
	}

	if($login == '') {
		$errmsg_arr[0] .= 'NIS / NIP / Email tidak boleh kosong<br />';
		$errflag = true;
	}

	if($password == '') {
		$errmsg_arr[0] .= 'Password tidak boleh kosong<br />';
		$errflag = true;
	}

	if($user_type == '') {
		$errmsg_arr[0] .= 'Tipe login tidak boleh kosong<br />';
		$errflag = true;
	}
	
	if($user_type!='') {
		if($user_type=='admin' || $user_type=='guru' || $user_type=='siswa') {
			if($user_type=='admin' || $user_type=='guru') {
				$user_id = 'nip';
			} elseif($user_type=='siswa') {
				$user_id = 'nis';
			}
			$qry="SELECT * FROM $user_type WHERE $user_id='$login' AND password='".md5($_POST['password'])."'";
			$res=mysql_query($qry);
			if(!$num=mysql_num_rows($res)) {
				$qry="SELECT * FROM $user_type WHERE $user_id='$login' AND password=''";
				$res=mysql_query($qry);
				if($num=mysql_num_rows($res) && $login<>$password) {
					$errmsg_arr[0] = 'Password Salah<br />';
					$errflag = true;		
				}
			}
		}
	
		if($user_type=='alumni' || $user_type=='orangtua') {
			$user_id = 'email';
			$qry="SELECT * FROM $user_type WHERE $user_id='$login' AND password='".md5($_POST['password'])."'";
			$res=mysql_query($qry);
			if(!$num=mysql_num_rows($res)) {
				$errmsg_arr[0] = 'Password salah<br />';
				$errflag = true;		
			} else {
				$qry="SELECT * FROM $user_type WHERE $user_id='$login' AND password='".md5($_POST['password'])."' AND kode=''";
				$res=mysql_query($qry);
				if(!$num=mysql_num_rows($res)) {
					$errmsg_arr[0] = 'Anda belum melakukan aktifasi,<br />silakan periksa email terlebih dahulu<br />';
					$errflag = true;		
				}
			}
		}
	}
	
	if($errflag) {
		$_SESSION['ERRMSG_ARR'] = $errmsg_arr;
		session_write_close();
		header("location: error.php");
		exit();
	}
	
	$result=mysql_query($qry);
	
	if($result) {
		if(mysql_num_rows($result) == 1) {
			session_regenerate_id();
			$user = mysql_fetch_assoc($result);
			$_SESSION['SESS_USER_ID'] = $user[$user_id];
			$_SESSION['SESS_USER_NAMA'] = $user['nama'];
			$_SESSION['SESS_USER_PASSWORD'] = $user['password'];
			$_SESSION['SESS_USER_EMAIL'] = $user['email'];
			$_SESSION['SESS_USER_TYPE'] = $user_type;
			
			$_SESSION['SESS_USER_JKELAMIN'] = $user['jeniskelamin'];
			$_SESSION['SESS_USER_TEMLAHIR'] = $user['tempatlahir'];
			$_SESSION['SESS_USER_TGLLAHIR'] = $user['tgllahir'];
			$_SESSION['SESS_USER_ALAMAT'] = $user['alamat'];
			$_SESSION['SESS_USER_STATUS'] = $user['status'];
			
			if(($user_type=='admin') || ($user_type=='guru')) {
				$_SESSION['SESS_USER_PENDIDIKAN'] = $user['pendidikan'];
				$_SESSION['SESS_USER_STATPEGAWAI'] = $user['statuskepegawaian'];
			}

			if(($user_type=='siswa') || ($user_type=='alumni')) {
				$_SESSION['SESS_USER_THNMASUK'] = $user['tahunmasuk'];
			}

			if($user_type=='siswa') {
				$_SESSION['SESS_USER_NAMAORTU'] = $user['namaorangtua'];
				$_SESSION['SESS_USER_KERJAORTU'] = $user['pekerjaanorangtua'];
			}

			if($user_type=='alumni') {
				$_SESSION['SESS_USER_THNKELUAR'] = $user['tahunkeluar'];
				$_SESSION['SESS_USER_PEKERJAAN'] = $user['pekerjaan'];
			}

			if($user_type=='orangtua') {
				$_SESSION['SESS_USER_NIS'] = $user['nis'];
				$_SESSION['SESS_USER_PEKERJAAN'] = $user['pekerjaan'];
			}

			$_SESSION['ERRMSG_ARR'][0] = "Anda login sebagai ".$_SESSION['SESS_USER_NAMA'].", selamat datang kembali.";
			session_write_close();
			header("location: index.php");
			exit();
		}else {
			$_SESSION['ERRMSG_ARR'][0] = "Password salah";
			session_write_close();
			header("location: error.php");
			exit();
		}
	}else {
		die("Query gagal : ".mysql_error());
	}
?>