请问各位高手,我用INPOUT32.DLL 操作并口时出现“外部组件发生异常”，代码如下：
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        [DllImport("inpout32.dll", EntryPoint = "Out32")]
        public static extern void Output(int adress, int value);
        [DllImport("inpout32.dll", EntryPoint = "Inp32")]
        public static extern int Input(int adress);
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
        }
        private void button1_Click(object sender, EventArgs e)
        {  
           
           Input( 888 );//从888（即0x378）端口读取数据
           Output(888, 4);//把4从888端口输出 0 0 0
           
         
        }
    }
 

}
请问是怎么回事？多谢！