Hallöchen,
blos den include verlagern:
<?php
include "authentification.php";
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Virtuelles Räumchen</title>
<style type="text/css" media="screen">
<!--
@import url("style.css");
-->
</style>
</head>
<?php
// hier ist der include zu spät dran :(
echo "<br><h>Virtuelles Räumchen Administration</h>";
echo "<div id="container">";
echo "<div id="container_head">";
echo "Administrationsbereich:";
echo "</div>";
echo "<div id="box">";echo "</div>";
echo "</div>";
?>
MfG
vaudi