Problem med session.cookie_lifetime

Kode 

<div id="bruger_boks"><h1><table><tr><td bgcolor=#2F8E29 width="180" align="center"><u>Bruger</u></td></h1></tr><tr><p><td bgcolor=#0D5511 width="180" align="left" style="margin-right: 15px;
margin-left: 15px;"><center><? if(!$denne_side == "http://bdigital.frac.dk/users/logud.php") { if(!$_SESSION['loget_in'] == 1) { if($login) { $db = mysql_connect("localhost", *****, '******);
mysql_select_db("bdigital", $db);
$foresp = mysql_query("SELECT firstname, username, surname, password, hp, e_mail, profiltekst FROM brugere WHERE username = '$username_logon' AND password = '$password_logon' ") or die(mysql_error()); $number = mysql_num_rows($foresp);
        if($number == 1) { $_SESSION['loget_in'] = 1;
                                         $_SESSION['Bnavn'] = $username_logon;
                                         $_SESSION['Pword'] = $password_logon;
                                         session.cookie_lifetime = 691200;
                                         echo "Du er logget ind<br><br>
<a href=\\"http://bdigital.frac.dk/users/logud.php\\">Log ud</a>
 "; } else { echo "En eller flere felter var enten ikke udfyldt eller også var oplysningerne forkerte"; } } else { ?>
 <form method=post action=<? echo "$denne_side"; ?>><input type=hidden name=login value=1>Brugernavn:<br><input type=text name=username_logon><br>Password:<br><input type=password name=password_logon><br><input type=submit value="Log ind"></form><a href="http://bdigital.frac.dk/users/opret.php">Opret bruger</a><? } } else { echo "Du er logget ind.<br><br>
<a href=\\"http://bdigital.frac.dk/users/logud.php\\">Log ud</a>"; } } else { echo "Du er logget ud"; } ?></td></tr></table></div>