PHP - MANTIS -PHP - NTLM

Hi, i have a problem taking the user name of windows in PHP Mantis 2.1.1 .

The problem appears when i modified headers.

I put this code in login.php:

$headers = apache_request_headers();

if (!isset($headers['Authorization'])){
header('HTTP/1.1 401 Unauthorized');
header('WWW-Authenticate: NTLM');
exit;
}

$auth = $headers['Authorization'];

if (substr($auth,0,5) == 'NTLM ') {
$msg = base64_decode(substr($auth, 5));
if (substr($msg, 0, 8) != "NTLMSSP\x00")
die('error header not recognised');

if ($msg[8] == "\x01") {
$msg2 = "NTLMSSP\x00\x02\x00\x00\x00".
"\x00\x00\x00\x00". // target name len/alloc
"\x00\x00\x00\x00". // target name offset
"\x01\x02\x81\x00". // flags
"\x00\x00\x00\x00\x00\x00\x00\x00". // challenge
"\x00\x00\x00\x00\x00\x00\x00\x00". // context
"\x00\x00\x00\x00\x00\x00\x00\x00"; // target info len/alloc/offset

header('HTTP/1.1 401 Unauthorized');
header('WWW-Authenticate: NTLM '.trim(base64_encode($msg2)));
exit;
}
else if ($msg[8] == "\x03") {
//$contenido = str_replace("\0", '',$msg,44);
function get_msg_str($msg, $start, $unicode = true) {
$len = (ord($msg[$start+1]) * 256) + ord($msg[$start]);
$off = (ord($msg[$start+5]) * 256) + ord($msg[$start+4]);
if ($unicode)
return str_replace("\0", '', substr($msg, $off, $len));
else
return substr($msg, $off, $len);
}

$user = get_msg_str($msg, 36);
$domain = get_msg_str($msg, 28);
$workstation = get_msg_str($msg, 44);
}

----

Then username is in $user, but when i make operations into Mantis i recived this error: APPLICATION ERROR #2800 "Invalid form security token."

Can anybody help me please ?

Thank You!!