When I make a call to my Web Service, I have a message:

Object reference not set to an instance of an object

This is my import status:

Imports System.Web.Services
Imports System.IO
Imports System.XML
Imports Microsoft.Web.Services
Imports Microsoft.Web.Services.Dime

And, this is the method which is concerned:

   <WebMethod()> _
   Public Function UTDCDownloadFile(ByVal tnNumero As Integer) As String
      '      Return Me.GetData("2," + tnNumero.ToString, 7)

      ' Get the SoapContext for the response message
      Dim loContext As SoapContext
      loContext = HttpSoapContext.ResponseContext

      ' Get the file name
      Dim lcFile As String
      lcFile = "D:\IIS\Universa\About1.jpg"

      ' Create a new DIME attachment using the the file name and 
      ' specifying the encoding of the attachment using the MIME media type
      Dim loDimeAttachment As DimeAttachment
      loDimeAttachment = New DimeAttachment("image/jpeg", TypeFormatEnum.MediaType, lcFile)

      ' Generate a GUID-based URI reference for the attachment object
      ' and assign in to the ID property of the DIME record
      loDimeAttachment.Id = "uri:" + Guid.NewGuid().ToString()

      ' Add the new DimeAttachment object to the SoapContext object
      loContext.Attachments.Add(loDimeAttachment)

      ' Return the file name of the attachment
      Return "About1.jpg"

   End Function

The error is reported on the line:

      loContext.Attachments.Add(loDimeAttachment)

Anyone knows what I am missing?