FluentNhibernate TypeLoadException

我正试图使用Fluenthibernate构建一个示例MVC3项目，当我试图创建会话工厂时，我得到了一个typeloadexception。

会话工厂

//using System;
//using NHibernate;
//using NHibernate.Cfg;
//using FluentNHibernate.Cfg;
//using FluentNHibernate.Cfg.Db;
//using System.Collections.Generic;
//using System.Linq;
//using System.Web;
//using System.Web.Mvc;    
public class SessionProvider
{
    public SessionProvider ()
    {
    }
    public static ISessionFactory BuildFactory()
{
    return Fluently.Configure()//Explosion here
          .Database(MySQLConfiguration.Standard.ConnectionString(
          c => c.FromConnectionStringWithKey("DashboardModels")
      ))
    .Mappings(m => m.FluentMappings.AddFromAssemblyOf<Accounts>())
    .BuildSessionFactory();
}
}

Global。Asax

public class MvcApplication : System.Web.HttpApplication
{
    public static ISessionFactory SessionFactory =
             SessionProvider.BuildFactory();
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new HandleErrorAttribute());
    }
    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
        routes.MapRoute(
            "Default", // Route name
            "{controller}/{action}/{id}", // URL with parameters
            new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
        );
    }
    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        RegisterGlobalFilters(GlobalFilters.Filters);
        RegisterRoutes(RouteTable.Routes);
    }
}

异常

System.TypeInitializationException: An exception was thrown by the type initializer for 
System.Web.Configuration.WebConfigurationManager ---> System.Exception: Method not found: 'System.Configuration.ConfigurationManager.get_ConfigurationFactory'.
  --- End of inner exception stack trace ---
  at (wrapper xdomain-invoke) System.AppDomain:DoCallBack (System.CrossAppDomainDelegate)
  at (wrapper remoting-invoke-with-check) System.AppDomain:DoCallBack (System.CrossAppDomainDelegate)
  at System.Web.Hosting.ApplicationHost.CreateApplicationHost (System.Type hostType, System.String virtualDir, System.String physicalDir) [0x00000] in <filename unknown>:0
  at Mono.WebServer.VPathToHost.CreateHost (Mono.WebServer.ApplicationServer server, Mono.WebServer.WebSource webSource) [0x00000] in <filename unknown>:0
 at Mono.WebServer.XSP.Server.RealMain (System.String[] args, Boolean root, IApplicationHost ext_apphost, Boolean quiet) [0x00000] in <filename unknown>:0
 at Mono.WebServer.XSP.Server.Main (System.String[] args) [0x00000] in <filename unknown>:0

我过去在其他地方使用过这个确切的代码，没有任何问题，我不知道可能是什么问题。我是不是做错了什么？