<?php

ob_start();

$host="localhost"; // Host name

$username=""; // Mysql username

$password=""; // Mysql password

$db_name="log"; // Database name

$tbl_name="administrator"; // Table name

// Connect to server and select databse.

mysql_connect("$host", "$username", "$password")or die("cannot connect");

mysql_select_db("$db_name")or die("cannot select DB");

// Define $myusername and $mypassword

$myusername=$_POST['myusername'];

$mypassword=$_POST['mypassword'];

$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";

$result=mysql_query($sql);

if(!$result){

die(mysql_error());

}

// Mysql_num_row is counting table row

$count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){

// Register $myusername, $mypassword and redirect to file "login_success.php"

session_register("myusername");

session_register("mypassword");

header("location:login_success.php");

}

take a look at the session_register

it should be:

session_register($myusername);