Upload files problem

I have a problem with the fckeditor into the upload files in the server,

When I press to see the server, I get an error on page

http://xxxxxx.com/FCKeditor/editor/file ... ector.aspx

The error is:

Line:120
Char:2
Error: Object required
Code: 0

URL: http://.........com/FCKeditor/editor/fi ... slist.html

Javascript error:
this.DOMDocument has no properties

Javascript error line
var xPathResult = this.DOMDocument.evaluate( xpath, this.DOMDocument,
102 this.DOMDocument.createNSResolver(this.DOMDocument.documentElement), 9, null);

Please help me! thanks