I don't usually don't have a problem. This is my script below, following my error message. I've tried everything. What I'm I missing?

<img src="images/flightattendant.jpg" alt="Jeanne - Your flight attendant" width="378" height="851" align="right" />

<?php
Session_start();
// Force script errors and warnings to show on page in case php.ini file is set to not display them
Error_reporting(E_ALL);
Ini_set('display_errors', '1');

// Unset all of the session variables
$_SESSION = array();
// If it's desired to kill the session, also delete the session cookie
If (isset($_COOKIE['idCookie'])) {
setcookie("idCookie", '', time()-42000, '/');
setcookie("locaCookie", '', time()-42000, '/');
}
// Destroy the session variables
Session_destroy();

// Check to see if their session is in fact destroyed
If(!session_is_registered('firstname')){
print "Bon Voyage... Every goodbye makes the next hello closer</font>.";

exit();

Header("location: index.php"); // << makes the script send them to any page we set
} else {

Print "<h2>Sorry - You're not able to depart at this time.</h2>";

Exit();

}

?>

ERROR:

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/********/public_html/root/logout.php:2) in /home/********/public_html/root/logout.php on line 3

Bon Voyage... Every goodbye makes the next hello closer.

Move the image tag below the script. You cannot have any output/text or anything else before a session_start() call. This has to do with response headers and cookies. For details on why that is please review the PHP documentation on sessions PHP: Sessions - Manual

For future reference the same goes for a call to the header() function for the same reason as above.