ExtractIconExW Issue

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Drawing;
using Microsoft.Win32;

namespace ConsoleApplication1
{
    class Program
    {
        [DllImport("Shell32.dll", EntryPoint = "ExtractIconExW", CharSet = CharSet.Unicode, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
        private static extern int ExtractIconEx(string sFile, int iIndex, out IntPtr piLargeVersion, out IntPtr piSmallVersion, int amountIcons);

        static void Main(string[] args)
        {
            IntPtr largeIconPtr = IntPtr.Zero;
            IntPtr smallIconPtr = IntPtr.Zero;

            //HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{1206F5F1-0569-412C-8FEC-3204630DFB70}\DefaultIcon
            Console.WriteLine("Vault.dll");
            ExtractIconEx(@"%SystemRoot%\system32\Vault.dll", 1, out largeIconPtr, out smallIconPtr, 1);
            Console.WriteLine("Icon Index = 1");
            Console.WriteLine("Large: " + largeIconPtr.ToString());
            Console.WriteLine("Small: " + smallIconPtr.ToString());
            Console.WriteLine();

            Console.WriteLine("Icon Index = -1");
            ExtractIconEx(@"%SystemRoot%\system32\Vault.dll", -1, out largeIconPtr, out smallIconPtr, 1);            
            Console.WriteLine("Large: " + largeIconPtr.ToString());
            Console.WriteLine("Small: " + smallIconPtr.ToString());
            Console.WriteLine();

            //HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{40419485-C444-4567-851A-2DD7BFA1684D}\DefaultIcon
            Console.WriteLine("telephon.cpl");
            Console.WriteLine("Icon Index = 100");
            ExtractIconEx(@"%SystemRoot%\System32\telephon.cpl", 100, out largeIconPtr, out smallIconPtr, 1);
            Console.WriteLine("Large: " + largeIconPtr.ToString());
            Console.WriteLine("Small: " + smallIconPtr.ToString());
            Console.WriteLine();

            Console.WriteLine("Icon Index = -100");
            ExtractIconEx(@"%SystemRoot%\System32\telephon.cpl", -100, out largeIconPtr, out smallIconPtr, 1);
            Console.WriteLine("Large: " + largeIconPtr.ToString());
            Console.WriteLine("Small: " + smallIconPtr.ToString());
            Console.ReadLine();
        }
    }
}