documentElement ist nil

[Luckie]

Ich versuche gerade daten in eine XML-Datei zu schreiben:

Delphi-Quellcode:

procedure TContactCollection.SaveToXMLFile;

  procedure WriteFileInfo;
  begin

  end;

  procedure WriteContact(Contact: TContact);
  var
    NewNode         : IXMLDOMNode;
  begin
    if FXMLDoc.documentElement = nil then Exit;

    NewNode := FXMLDoc.createElement('Kontakt');
    if (NewNode <> nil) then
    try
      createElement(FXMLDoc, NewNode, 'Name', Contact.Name);
      createElement(FXMLDoc, NewNode, 'Vorname', Contact.Vorname);
      createElement(FXMLDoc, NewNode, 'Strasse', Contact.Strasse);
      createElement(FXMLDoc, NewNode, 'PLZ', Contact.PLZ);
      createElement(FXMLDoc, NewNode, 'Ort', Contact.Ort);
      createElement(FXMLDoc, NewNode, 'Land', Contact.Land);
      createElement(FXMLDoc, NewNode, 'Telefon1', Contact.Telefon1);
      createElement(FXMLDoc, NewNode, 'Telefon2', Contact.Telefon2);
      createElement(FXMLDoc, NewNode, 'EMail1', Contact.EMail1);
      createElement(FXMLDoc, NewNode, 'EMail2', Contact.EMail2);
      createElement(FXMLDoc, NewNode, 'URL', Contact.Homepage);
      createElement(FXMLDoc, NewNode, 'GebDat', Contact.GebDat);
      createElement(FXMLDoc, NewNode, 'Firma', Contact.Firma);
      // createElement(FXMLDoc, NewNode, 'Bem', Contact.Bem);
      // neuen Knoten anhängen
      FXMLDoc.documentElement.appendChild(NewNode);

    finally
      NewNode := nil;
    end;
  end;

var
  i                 : Integer;

begin
  FXMLDoc := CoDOMDocument40.Create;
  FXMLDoc.async := false;
  FXMLDoc.resolveExternals := false;
  FXMLDoc.preserveWhiteSpace := false;

  // wenn XML-Adressdatei nicht existiert, neu anlegen
  if (not FileExists(FFilename)) then
  begin
    FXMLDoc.loadXML('<?xml version="1.0" encoding="ISO-8859-1"?><adressdb/>');
  end;

  //WriteFileInfo;

  for i := 0 to Self.Count - 1 do
  begin
    WriteContact(Self.Items[i]);
  end;
  FXMLDoc.save(FFilename);
end;

Jetzt musste ich aber feststellen, dass in der Prozedur WriteContact die Eigenschaft documentElement von FXMLDoc nil ist. Wie kommt das? Was habe ich vergessen?