Hi Marius,
"I've seen this exception before but I don't remember how to avoid it.
What version of the WYSIWYG editor do you use? Is your Wysiwyg.html file
similar to this
http://svn.xwiki.org/svnroot/xwiki/platform/web/tags/xwiki-web-2.1.1/wysiwy…
?"
It is similar, here is what I got:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html 
xmlns="http://www.w3.org/1999/xhtml" lang="en"
xml:lang="en">
<head>
  <title>XWiki WYSIWYG Editor - Hosted Mode Demo</title>
  <meta name="gwt:property" content="locale=en" />
  <script type="text/javascript"
src="/xwiki/resources/js/prototype/prototype.js"></script>
  <script type="text/javascript"
src="/xwiki/bin/skin/resources/js/xwiki/xwiki.js"></script>
  <script type='text/javascript'
src='/xwiki/bin/skin/resources/js/smartclient/initsc.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/modules/ISC_Core.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/modules/ISC_Foundation.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/modules/ISC_Containers.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/modules/ISC_Grids.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/modules/ISC_Forms.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/modules/ISC_DataBinding.js'></script>
  <script type='text/javascript'
src='/xwiki/resources/js/smartclient/skins/Enterprise/load_skin.js'></script>
  <script type='text/javascript'
src='/xwiki/bin/skin/resources/js/xwiki/xwikiexplorer/xwikiexplorer.js'></script>
  <script type="text/javascript"
src="xwe.nocache.js"></script>
</head>
<body>
  <button onclick="load(this)">Load</button>
  <script type="text/javascript">
    function load(hook) {
      // Create a plain text area.
      var textArea = document.createElement('textarea');
      textArea.id = 'demo';
      textArea.rows = 25;
      textArea.cols = 80;
      hook.parentNode.replaceChild(textArea, hook);
      // Create a new editor instance.
      new WysiwygEditor({
        hookId: 'demo',
        syntax: 'xwiki/2.0',
        displayTabs: true,
        defaultEditor: 'wysiwyg',
        plugins: 'submit line separator text valign list indent history
format symbol link image table macro import',
        menu: 'link image table macro import',
        debug: true
      });
    }
  </script>
</body>
</html>
What should I do? Thank you for your help!
Jue Wang