php login-script hjälp

php login-script hjälp

hej jag försöker includa detta script:

<?
session_start();
$losen = "admin";
$user = "admin";
if ($_GET == "ja") {
if ($_POST == $user) {
if ($_POST == $losen) {
$_SESSION = "ja";
} else {
$_SESSION = "Du angav fel användarnamn eller lösenord";
}
}
}
if ($_SESSION != "ja") {
?>
<form name="form" method="post" action="admin.php?loggain=ja"& gt;
<br>
Användarnamn:<br>
<input name="anvandarnamn" type="text" id="anvandarnamn">
<br>
Lösenord:<br>
<input name="losenord" type="password" id="losenord">
<br>
<input name="submit" type="submit" value="submit">
</form>
<?
echo $_SESSION;
} else {
?>


<?
}
?>

på detta vis: <? include("admin.php");?>

men får detta felmeddelande: Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /home/gallo/public_html/test/create/index.php:10) in /home/gallo/public_html/test/create/inde x.php on line 19

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home/gallo/public_html/test/create/index.php:10) in /home/gallo/public_html/test/create/inde x.php on line 19