I am using Master Page. I upgraded the AJAX control softwarekit to 4.1.60623 (6 25 2012).
The OnUploadComplete event handler for ajaxfileupload does not edit the server control on the page like label, textbox, neither could it modify the seestate variable of the page. It seems to me that this server function does not do postback of any kind.
This could trigger the postback, and, using some hidden fields, I could manage to resolve the hardy.
But I am admiring if there is some easyr way to let the OnUploadComplete event handler run the server code snippet and edit the server control directly