Error: The server didn't send back a proper XML response.

Hi all,
Initially when I implemented my fckeditor in the server and when I tried to upload images into the server using the fckeditor resources browser, it works fine. But after few months, suddenly this error message prompt out.


"The server didn't send back a proper XML response. Please contact your system administrator.

XML request error: OK(200)

Requested URL:
http://..............................

Response Text:
<?xml version="1.0" encoding="utf-8"?><Connector command="GetFoldersAndFiles" resourceType="FIle">.........</Connector>
"
My server is running using PHP/MySQL. It still running fine in my localhost but only occurs error in server. Can anybody knows how to fix this error?Thanks a lot. This is urgent. Appreaciate a lot.