Empty file not recognised by file upload control

hi Friends,
            i am using Ajax File Upload Control in my Application,in my Application I am Getting One Problem that is when i am uploading Empty File
the File upload Property hasfile Returning False, please give me Suggetion for my Problem. below is the code i used im My Application
    Function ValidateENotice() As Boolean
        Try
            Dim strDocsMapPath As String
            If fldAttachDocument.HasFile Then
                If Not (Trim(fldAttachDocument.PostedFile.FileName) = "") Then
                    If (fldAttachDocument.Po ...