I was actually not going to, and am afraid of asking such a silly question, but i have completely no clue what is going wrong here.
My JavaScript
function ahah(url, target) {
  document.getElementById(container).innerHTML = ' Fetching data...';
  if (window.XMLHttpRequest) {
    req = new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    req = new ActiveXObject("Microsoft.XMLHTTP");
  }
  if (req != undefined) {
    req.onreadystatechange = function() {ahahDone(url, target);};
    req.open("GET", url, true);
    req.send("");
  }
}  
function ahahDone(url, target) {
  if (req.readyState == 4) { // only if req is "loaded"
    if (req.status == 200) { // only if "OK"
      document.getElementById(container).innerHTML = req.responseText;
    } else {
      document.getElementById(container).innerHTML=" AHAH Error:\n"+ req.status + "\n" +req.statusText;
    }
  }
}
function load(name, div) {
    ahah(name,div);
    return false;
}
My HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
    <title>Container</title> 
<!-- GET YOURSELF SOME JAVASCRIPT -- >
    <script type="text/javascript" src="mootools.svn.js"></script>
    <!--script type="text/javascript" src="js/jQuery.js"></script-->    
    <script type="text/javascript" src="js/reflection.js"></script> 
    <script type="text/javascript" src="js/jquery.js"></script>
    <!--script type="text/javascript" src="js/javas.js"></script-->
    <script type="text/javascript" src="js/getstuff.js"></script>
    <script type="text/javascript" src="js/ahah.js"></script>
    <script type="text/javascript">
     window.addEvent('domready', function(){
     var mySlide = new Fx.Slide('top-panel');
     mySlide.hide(); $('toggle').addEvent('click', function(e){
     e = new Event(e);
     mySlide.toggle();
     e.stop();
     });
     });
    </script>
    <!--script type="text/javascript" src="js/request.js"></script-->
</head>
<link rel="stylesheet" type="text/css" href="style.css" />
<body onload="getlogo()">
<div id="top-panel">
    <!-- Top Panel content here -->
    <table class="panel" border="0" width="100%" align="center">
    <tr>
     <td></td>
     <td align="left" width="15%">
      <ul>
       <li> <a href="index.html" class="panel">Home (F5)</a></li>
       <li> <a href="#" class="panel" onclick="gettermine()">Termine</a></li>
       <li> <a href="#" class="panel" onclick="getsomethingelse()">Material</a></li>
      </ul>
     </td>
     <td align="left" width="30%">
      <ul>
       <li> <a href="#" class="panel" onclick="getsomethingelse()">Flechten mit frischen Weiden</a></li>
       <li> <a href="#" class="panel" onclick="getsomethingelse()">Flechten mit getrockneten Weiden</a></li>
       <li> <a href="#" class="panel" onclick="getanfahrt()">Anfahrt</a> </li>
      </ul>
     </td>
     <td align="left" width="15%">
      <ul>
       <li> <a href="#" onclick="getsomethingelse()" class="panel">Hauswurz</a> </li>
       <li> <a onclick="getsomethingelse()" href="#" class="panel">Kontakt</a> </li>
       <li> <a onclick="getsomethingelse()" href="#" class="panel">Impressum</a> </li>
      </ul>
     </td>
     <td align="left" width="15%">
      <ul>
       <li> <a href="#" onclick="getsomethingelse()" class="panel">Support</a> </li>
       <li> <a href="about.html" onclick="load('about.html','container');return false;" class="panel">Profil</a> </li>
      </ul>
     </td>
    </tr>
    </table>
</div>
<div id="sub-panel">
    <a href="#" id="toggle"><span>Mehr</span></a>
</div>
<!--div id="container"-->
<div id="container">
    <div id="logo">
     <!--img src="img/logo.png"-->
    </div>
    <div align="center" id="tagline"> 
     <a onclick="getanfahrt()" class="navlink" href="#">Fricker 1, 88285 Bodnegg</a> | <a href="#" class="navlink" onclick="getkontakt()">07520/914249</a> | <a class="navlink" href=mailto:[email protected]>[email protected]</a>
    </div>
</div>
</body>
</html>
The JavaScript should be executed by the link:
<a href="about.html" onclick="load('about.html','container');return false;" class="panel">
But when the link is clicked, nothing happens. Firebug says that everything is loaded fine.
It would be really great if someone would leave the answer with a short explanation!
Thanks a lot in advance!