change directory access control for common application data folder failed.

Question

Here is my code, and i tried same code for file access control, it works well. but doesn't work for common application data on Vista.

private static void GrantEveryoneFullControlRight(string directory)
        {
            try
            {
                if (!Directory.Exists(directory))
                    Directory.CreateDirectory(directory);

                DirectoryInfo dirInfo = new DirectoryInfo(directory);
                DirectorySecurity ds = dirInfo.GetAccessControl(AccessControlSections.Access);

                FileSystemAccessRule rule = new FileSystemAccessRule(
                    "Users", FileSystemRights.FullControl, AccessControlType.Allow);

                ds.AddAccessRule(rule);
                dirInfo.SetAccessControl(ds);


            }
            catch (Exception ex)
            {
                // Logger.WriteLog(LogType.Error, ex.ToString());
                Console.WriteLine(ex.ToString());
            }
        }