HI rathiDigimagic,

Do you get this error with speical file/size/extension? Or it is a randomly problem?

Please set  UploadType to iframe and set UploaderDebug to 1 then try again. what error message you get form the debug window?

        <CuteWebUI:UploadAttachments ID="uploader1" runat="server" UploadType="iframe" UploaderDebug="1">
        </CuteWebUI:UploadAttachments>

Is your site online? if so, can you post your uploader page url? So we can check it for you directly.

Regards,

Ken