You have an error in your SQL syntax.

Hejsa jeg får en meget lang fejl, nemlig denne:

You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
Warning: Unknown(): Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively. in Unknown on line 0

Koden er her:

<?
session_start();

include('sql.php');

$brugernavn = $_POST[brugernavn];
$kode = md5($_POST[kode]);

$tjek = mysql_query("SELECT * FROM woox_brugere WHERE brugernavn = '$brugernavn' AND kode = '$kode'") or die(mysql_error());

$aktiv = mysql_fetch_array($tjek);

if(mysql_num_rows($tjek) == '0') {

header("Location: main.php?side=forkert_login");

} elseif($aktiv[aktiv] == 'nej') {

header("Location: main.php?side=forkert_aktiv");

} else {

$row = mysql_fetch_array($tjek);

$_SESSION[brugernavn] = $row[brugernavn];
$_SESSION[brugerid] = $row[id];


mysql_query("UPDATE woox_brugere SET online= 'ja' WHERE id=".$_SESSION[brugerid]."")  or die(mysql_error());

}
?>
<SCRIPT type="text/javascript">
java script:history.back(1)
</script>Hvis der ikke sker noget så tryk <a href="index.php">her</a>.