idhttp post file - multipart form data with indy?

hi

I am trying to upload a file to an https server through indy 9.0

I have looked at the articles on the nevrona site and an doing what they say, but...

when I do this - addfile procedure I get an error message "unable to open file"

var
  ResponseStream: TMemoryStream;
  MultiPartFormDataStream: TidMultiPartFormDataStream;
begin
  Form1.OpenDialog1.Title := 'are you sure you want to upload information';
  if form1.OpenDialog1.Execute then
  begin
    MultiPartFormDataStream := TidMultiPartFormDataStream.Create;
    ResponseStream := TMemoryStream.Create;
    try
      form2.IdHttp1.Request.ContentType := MultiPartFormDataStream.RequestContentType;
      MultiPartFormDataStream.AddFormField('PersonName', form2.Edit1.Text);
      MultiPartFormDataStream.AddFile('c:\file.doc', form1.opendialog1.Files.Text, 'application/msword');
      { You must make sure you call this method *before* sending the stream }
    //  MultiPartFormDataStream.PrepareStreamForDispatch;
      MultiPartFormDataStream.Position := 0;
      form2.IdHTTP1.Post('https://webdev.hort.cri.nz\test\post_test.php', MultiPartFormDataStream, ResponseStream);
    finally
      MultiPartFormDataStream.Free;
      ResponseStream.Free;
    end;
  end;

can anyone please help with this?  I desperately need to be able to upload a file to our https server

can anyone help with advice, pointers to more articles or examples?

Cheers

Chris