hvorfor gir den fejl i mine if sætning

<?
include "bin_lib/definitions.php";
include "bin_lib/functions.php";
include "bin_lib/copyright.php";

$wn=date("z");
$wn=ceil($wn/7);
$KursusSlutUge=38;
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
<HTML>
<HEAD>
    <TITLE>Kursusoversigt - AutoCAD 2004</TITLE>
<META NAME="Generator" CONTENT="Stone's WebWriter 3.5">
<LINK REL="stylesheet" HREF="styles/style.css" TYPE="text/css">

</HEAD>
<BODY CLASS="top">
<FONT SIZE="6">Kursusoversigt - AutoCAD 2004</FONT><BR>
Version 1.3 <IMG SRC="images/beta.gif" BORDER="0" WIDTH="55" HEIGHT="30" ALIGN="bottom" ALT=""><HR>
<A HREF="?valg=1" CLASS="choise">Book en plads</A> | <A HREF="?valg=3" CLASS="choise">Se deltagerne på holdet</A>| <A HREF="?valg=5" CLASS="choise">Slet tilmelding</A><BR><BR>
<?
if ($valg==1){
include "SideA.php";
} elseif ($valg==3){
include "SideB.php";
} elseif ($valg==5){
include "SideC.php";
} else {
include "bin_lib/fortext.txt";
}
?>
</BODY>
</HTML>