images in itextsharp

Hi, i have a problem here where i am using itextsharp to convert  an image in my application folder into pdf.Somehow, when i click the button, an error occurs telling me that pdf has no page.Heres what i did in a button. Can anyone help me? thx
Dim document As New Document(PageSize.A4.rotate())Dim writer = PdfWriter.getInstance(document, New FileStream(System.AppDomain.CurrentDomain.BaseDirectory() & "test.pdf", FileMode.Create))document.Open()Dim jpeg As iTextSharp.text.Image = iTextSharp.text.Image.getInstance("dog.jpg")jpeg.scaleToFit(PageSize.A4.Wid ...