Convert PDF to Tiff files via HTTP upload - Code issues

Protected Sub UpdateFile()
        Dim _uldfile As HttpPostedFile
        Dim _int As Integer
        Dim _fileName As String
        Dim _fileExtension As String
        Dim _uldFileName As String
        Dim _NewTiffFileName As String
        Dim _ErrMessage As String
        Dim _codecs As Leadtools.Codecs.RasterCodecs = Nothing
        Dim _imageObject As Leadtools.RasterImage = Nothing
        For Each s As String In Request.Files
            _uldfile = Request.Files(s)
            _int = _uldfile.ContentLength
            _fileName = _uldfile.FileName
            _fileExtension = String.Empty
            If Not (String.IsNullOrEmpty(_fileName)) Then
                _fileExtension = System.IO.Path.GetExtension(_fileName)
            End If
            _uldFileName = System.Guid.NewGuid().ToString
            _NewTiffFileName = Server.MapPath("~/UploadFiles/") & _uldFileName & ".tif"
            Leadtools.Codecs.RasterCodecs.Startup()
            _codecs = New Leadtools.Codecs.RasterCodecs()

            Dim info As CodecsImageInfo
            info = _codecs.GetInformation(_uldfile.InputStream, True)
            If info.Format = Leadtools.RasterImageFormat.RasPdf Then
                _imageObject = _codecs.Load(_uldfile.InputStream)
                _codecs.Options.Pdf.Load.XResolution = info.XResolution
                _codecs.Options.Pdf.Load.YResolution = info.YResolution
                _codecs.Options.Tiff.Save.UsePhotometricInterpretation = True
                _codecs.Options.Tiff.Save.PhotometricInterpretation = CodecsTiffPhotometricInterpretation.MinimumIsWhite
                _codecs.Save(_imageObject, _NewTiffFileName, Leadtools.RasterImageFormat.Tif, 0, 1, -1, 1, CodecsSavePageMode.Overwrite)
            Else
                _imageObject = _codecs.Load(_uldfile.InputStream)
                _codecs.Options.Save.UseImageDitheringMethod = True
                _imageObject.DitheringMethod = Leadtools.RasterDitheringMethod.FloydStein
                Try
                    _codecs.Save(_imageObject, _NewTiffFileName, Leadtools.RasterImageFormat.Tif, 32)
                Catch ex As Exception
                    _ErrMessage = ex.Message
                Finally
                End Try
                _imageObject.Dispose()
                _codecs.Dispose()
            End If
        Next

    End Sub