="公共语言运行库检测到无效的程序。"???? 是微软的bug吗？

用户代码未处理 System.InvalidProgramException
  Message="公共语言运行库检测到无效的程序。"
  Source="WindowsApplication1"
  StackTrace:
       在 WindowsApplication1.Winvoker.Invokess[T](Control ctrl, Invokes`1 i, T value)
       在 WindowsApplication1.Form1.Set() 位置 D:\我的文档\Visual Studio 2005\Projects\WindowsApplication1\WindowsApplication1\Form1.cs:行号 25
       在 System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
       在 System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
       在 System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage msg, IMessageSink replySink)

using System;
using System.Collections.Generic;

using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            new Pixysoft.MultiThread.AsyncMethodHelper(Set).Do();
        }

        private void Set()
        {
            Winvoker.Invokess<string>(label1, SetText, "asdf");

        }

        private void SetText(string mes)
        {
            label1.Text = "sdf";
        }
    }

    public class Winvoker
    {
        public delegate void Invokes<T>(T value);

        private delegate void DInvokes<T>(Control ctrl, Invokes<T> i, T value);

        public static void Invokess<T>(Control ctrl, Invokes<T> i, T value)
        {
            if (ctrl.InvokeRequired)
                ctrl.Invoke(new DInvokes<T>(Invokess<T>), new object[] { ctrl, i, value });
            else
                i(value);
        }
    }
}