Session virker ikke?

filen index.php
<?php
session_start();

//udskriver info (test1)
echo $_SESSION['login_status'];
echo $_SESSION['username'];
echo $_SESSION['password'];

if($_SESSION['login_status'] !== 'on'){
print 'Your are not logget in!<br>
<form method="POST" action="?q=login">
User <input type="text" name="username" size="15" style="font-family: Tahoma; font-size: 8pt; border: 1px dotted #000000"><br>
Pw <input type="text" name="password" size="15" style="font-family: Tahoma; font-size: 8pt; border: 1px dotted #000000"><br>Create user<br>
<input type="submit" value="Login" name="login"></form>';
}
else {
echo "du er inde";
}

if($_GET[q]){
include("$_GET[q].php");
if(empty($_GET[q]))$_GET[q]="main";
} else {
include("main.php");
}
?>

filen login.php

<?php
session_start();

$username = $_POST['username'];
$password = $_POST['password'];


if (empty($username) or empty($password)){
print('<script type="text/javascript">window.location="?q=fejl1"</script>');
}

include "connect.php";

$res = mysql_query("SELECT * FROM users where username='$username' AND password='$password'") or die ("Error 006");
$show = mysql_num_rows($res);

if ($show !== 1){
    print('<script type="text/javascript">window.location="?q=fejl2"</script>');
}
else {

    $_SESSION['username'] = $username;
    $_SESSION['password'] = $password;
    $_SESSION['login_status'] = on;

//udskriver info (test2)
echo $_SESSION['login_status'];
echo $_SESSION['username'];
echo $_SESSION['password'];

    //print('<script type="text/javascript">window.location="?q=inde"</script>');

}
?>

efter login viser test2 info mens test1 der er ovenover intet viser.. hvorfor virker det ikke?