When trying to upload images through FCK Editor tool inside an aspx page it throws an  error[XML 403 path Error].

To Fix the issue we have to configure manually.

STEP-I :

File Path  :  fckeditor/fckconfig.js
Previously :
var _FileBrowserLanguage    = 'asp' ;  // asp | aspx | cfm | lasso | perl | php | py
var _QuickUploadLanguage    = 'asp' ;  // asp | aspx | cfm | lasso | perl | php | py

We have to change 'asp' to 'aspx'

STEP-II

File Path  :  fckeditor\editor\filemanager\connectors\aspx\config.ascx

Previously :

Change-1 : Enabled = CheckAuthentication();
                       
                          Change-2 : UserFilesPath = "~/upload/";
 
           Change-3 : UserFilesAbsolutePath = "C:\\upload\\";

Change -1 : change it to Enable = true;
Change -2 : change the folder name in which you want to store the uploaded image.
Change -3 : change the absolute path of the folder in which you want to store the uploaded image.