Unable to cretae Virtual Directory in IIS 7.5

hello,
i am writing following code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.DirectoryServices;
using System.DirectoryServices.ActiveDirectory;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Collections;


public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //Create a virtual directory


        CreateSite("IIS://Localhost/W3SVC", "555", "Email", @"C:\Email");

        SetSingleProperty("IIS://Localhost/W3SVC/555", "ServerBindings", ":8 ...