why doesn't this work??

In an includefile (a menu...) I carry following code which doesn't work.:
QUOTE==
<?php
if($IsLoggedIn)
{
?>
<td>BLABLA</td>
<?php
}
else
{
?>
<td>BLEBLE</td>
<?php
}
?>
UNQUOTE==

In the file where the include is part I have in top of file following, which I think was as I understood meant to be:
QUOTE==
<?php
ini_set ("include_path",'includes');
include('javascripts.php');
include('class.security.php');
include('header.php');
include('menu.php');

$dtlsSecurity = new Security;

$dtlsSecurity->ExtraFieldNames('firstname,lastname');
$dtlsSecurity->StoreSession_TableName('session');
$dtlsSecurity->Log_TableName('log');
$dtlsSecurity->FieldNames('sessionid', 'userid', 'username', 'auth');

$IsLoggedIn = $dtlsSecurity->IsLoggedIn();
$details = $dtlsSecurity->GetData();


if(!$dtlsSecurity->IsLoggedIn() && !is_numeric(strpos($_SERVER["PHP_SELF"], "login.php")))
{
if($_COOKIE['mem'] != '')
{
header("location: login.php?strMethod=checklogin");
}
}
?>

Any clues why still not working???? Thanks,
Martin

please dont post the same question twice.