Why does call to included function say "Undefined"

[maxwell_]

I have a logout function in a functions file

function logout2(){

$logoutAction = $_SERVER['PHP_SELF']."?doLogout=true";
if ((isset($_SERVER['QUERY_STRING'])) && ($_SERVER['QUERY_STRING'] != "")){
  $logoutAction .="&". htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($_GET['doLogout'])) &&($_GET['doLogout']=="true")){
  //to fully log out a visitor we need to clear the session varialbles
  $_SESSION['MM_Username'] = NULL;
  $_SESSION['MM_UserGroup'] = NULL;
  $_SESSION['PrevUrl'] = NULL;
  unset($_SESSION['MM_Username']);
  unset($_SESSION['MM_UserGroup']);
  unset($_SESSION['PrevUrl']);
$logoutGoTo = "logout.php";
  if ($logoutGoTo) {
    header("Location: $logoutGoTo");
    exit;
  }
}
}

I have a file that includes the functions file

require_once('includes/functions.php');

When I call the function on the page

logout2();

I get the following error message -

You don't have permission to access /tutor/<br /><b>Notice</b>: Undefined variable: logoutAction in <b>C:/www/server/public/tutor/softwarelist1.php</b> on line <b>62</b><br /> on this server.

Can someone please tell me why I am receiving this error.

[bradgrafelman]

Which line is line #62?

[maxwell_]

I seem to have fixed it by making my $logoutAction a global variable.
No error message now!

global $logoutAction;

function logout(){
global $logoutAction;
$logoutAction = $_SERVER['PHP_SELF']."?doLogout=true";
if ((isset($_SERVER['QUERY_STRING'])) && ($_SERVER['QUERY_STRING'] != "")){
  $logoutAction .="&". htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($_GET['doLogout'])) &&($_GET['doLogout']=="true")){
  //to fully log out a visitor we need to clear the session varialbles
  $_SESSION['MM_Username'] = NULL;
  $_SESSION['MM_UserGroup'] = NULL;
  $_SESSION['PrevUrl'] = NULL;
  unset($_SESSION['MM_Username']);
  unset($_SESSION['MM_UserGroup']);
  unset($_SESSION['PrevUrl']);
$logoutGoTo = "../../logout.php";
  if ($logoutGoTo) {
    header("Location: $logoutGoTo");
    exit;
  }
}
}