Problems creating own ToolbarSets

//My entry in the fckconfig.js
FCKConfig.ToolbarSets["Custom"] = [
   ['Bold','Italic','-','Link','Unlink','-','About']
] ;

<!--Part of the sourcecode of the webpage-->
<script type="text/javascript" src="/zaunbau/fckeditor/fckeditor.js"></script>
<script type="text/javascript">
var oFCKeditor = new FCKeditor('content_text');
oFCKeditor.BasePath = "/zaunbau/fckeditor/"; oFCKeditor.InstanceName = "content_text"; oFCKeditor.Width = "630px"; oFCKeditor.Height = "300px"; oFCKeditor.ToolbarSet = "Custom"; 
oFCKeditor.Create();
</script>