CSharp: Steuerung des Internet-Explorers: RFC ist nicht verfügbar

using System;
using System.Collections.Generic;
using System.Text;
using HttpWatch;
using System.Threading;
using SHDocVw;
using MSHTML;

...

            static void Test2()
            {
                object o = null;
                InternetExplorer ie = new InternetExplorerClass();
                IWebBrowserApp wb = (IWebBrowserApp)ie;

                wb.Navigate("http://www.live.com", ref o, ref o, ref o, ref o);  
                wb.Visible = true;

                ie.AddressBar = false;

                Thread.Sleep(5000);

                ie.AddressBar = true;

                ie.Quit();
            }

System.Runtime.InteropServices.COMException: "Der RPC-Server ist nicht verfügbar. (0x800706BA)"