Filename: redirection.config Error: Cannot read configuration file due to insufficient permissions

Hi
 
Filename: redirection.config Error: Cannot read configuration file due to insufficient permissions 

In C# Windows Application.
 
Am working on Windows 8.
 
this is my Code:

using (ServerManager serverManager = new ServerManager())
           {foreach (Site s in serverManager.Sites)
               {
                   Console.WriteLine("Site {0}", s.Name);
                   Console.ReadLine();foreach (Application app in s.Applications)
                   {
                       Console.WriteLine("\tApplication:{0}", app.Path);
                       Console.ReadLine();foreach (VirtualDirectory virdir in app.VirtualDirectories)
                       {
                           Console.WriteLine("\t\tVirtual Dir:{0}", virdir.Path);
                       }
                           Console.ReadLine();
                       }
                   }
               }

1.In Windows Explorer, locate the web.config file that is associated with the Web site. 
2.Right-click the web.config file 
3.Click Properties. 
4.Click the Security tab, and then click Edit. 
5.Click Add. 
6.In the Enter the object names to select box, type computername\IIS_IUSRS, click Check Names, and then click OK. 
Note Computername is a placeholder for the computer name. 
7.Click to select the Read check box, and then click OK. 
8.In the Web.config Properties dialog box, click OK.
 
I have tried this steps but still am getting Error.
 
can any one help me.
 
Thanks Regards

Sampath Kambala