ASP.NET

Hi,
I want to upload browsed file to the ftp server but getting this error
 

 Sub UploadFile()
 
        Try
            Dim fileName As String = FulFile.PostedFile.FileName
            Dim requestFTP As WebRequest = WebRequest.Create("ftp://...................." & fileName)
            requestFTP.Credentials = New NetworkCredential("userid", "password")
            requestFTP.Method = WebRequestMethods.Ftp.UploadFile
 

            Dim fStream As FileStream = FulFile.PostedFile.InputStream 'Error:Unable to cast object of type 'System.Web.HttpInputStream' to type 'System.IO.FileStream'.

 
            Dim bufferLength As Integer = 2048
            Dim buffer As Byte() = New Byte(bufferLength - 1) {}
 
            Dim uploadStream As Stream = requestFTP.GetRequestStream()
            Dim contentLength As Integer = fStream.Read(buffer, 0, bufferLength)
 
            While contentLength <> 0
                uploadStream.Write(buffer, 0, contentLength)
                contentLength = fStream.Read(buffer, 0, bufferLength)
            End While
            uploadStream.Close()
            fStream.Close()
            requestFTP = Nothing
 
            LblMsg.Text = "File Uploading Is SuccessFull..."
 
        Catch ep As Exception
            LblMsg.Text = ep.Message
        End Try
 
    End Sub