C#代码自动授予对Windows Server 2008上的文件夹的IIS写入权限？目前抛出异常

using System;
using System.IO;
using System.Security.AccessControl;

class Program
{
    static void Main()
    {
        string folderPath = @"C:\path\to\folder";

        try
        {
            // 获取文件夹的访问控制列表
            DirectorySecurity directorySecurity = Directory.GetAccessControl(folderPath);

            // 授予IIS用户写入权限
            string iisUser = "IIS_IUSRS";
            directorySecurity.AddAccessRule(new FileSystemAccessRule(iisUser, FileSystemRights.Write, InheritanceFlags.ContainerInherit | InheritanceFlags.ObjectInherit, PropagationFlags.None, AccessControlType.Allow));

            // 更新文件夹的访问控制列表
            Directory.SetAccessControl(folderPath, directorySecurity);

            Console.WriteLine("成功授予对文件夹的IIS写入权限。");
        }
        catch (Exception ex)
        {
            Console.WriteLine("授予对文件夹的IIS写入权限时发生异常： " + ex.Message);
        }
    }
}