SharePoint Online / Office 365 -- Client Object Model

Hello,

i try to get some Data from the SharePoint Online "Office365" Beta with the Client Object Model. I use an Sample from the MSDN but i always get the Error

"Server was unable to process request. ---> The server was unable to process the request due to an internal error. ...." in Visual Studio 2010.

Following the Code Snip:

  ClientContext clientContext = new ClientContext("https://URI.sharepoint.com/");

      clientContext.AuthenticationMode = ClientAuthenticationMode.FormsAuthentication;
      clientContext.FormsAuthenticationLoginInfo = new FormsAuthenticationLoginInfo("USER", "PASS");

      Web web = clientContext.Web;
      ListCollection allLists = web.Lists;

      clientContext.Load(web);
      clientContext.Load(allLists);

      clientContext.ExecuteQuery();
  
      Console.WriteLine("{0} ({1})", web.Title, web.Description);

      foreach (List list in allLists)
      {
        Console.WriteLine("{0} ({1})", list.Title, list.BaseType);
      }