CKFinder and CKEditor wont work

Hi all people...

I'm looking for a solution for my problem where CKFinder is not working in CKEditor. My problem is that javascript gives an error.

TypeError: Result of expression 'f' [undefined] is not an object.

(using debugger)
The file hierarchy of relevant files is as follows:

index.php
cybercat_files/
-ckeditor/
--ckfinder/
func_/
-func_geteditor.php

func_geteditor.php calls CKEditor and CKFinder with the following code:

<script type="text/javascript" src="'.$site_root.'/cybercat_files/ckeditor/ckeditor.js"></script>
<script type="text/javascript" src="'.$site_root.'/cybercat_files/ckeditor/ckfinder/ckfinder.js"></script>';
<script type='text/javascript'>
   window.onload = function()
   {
      var screener=CKEDITOR.replaceAll();
      CKFinder.setupCKEditor(screener, '/ckfinder/');
   }
   </script>

func_geteditor.php gets included in index.php.

What am I doing wrong and can sombody help me?