Writing TXT file to Share Problem?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            long lastCode = 28110000;
            int padSize = (lastCode == 0) ? 1 : (int)Math.Log10(lastCode) + 1;

            String filename = @"C:\Documents and Settings\All Users\Desktop\" + lastCode + "_sequentialCodes.txt";
            StreamWriter writer = new StreamWriter(filename, false, Encoding.ASCII);
            writer.AutoFlush = true;

            for (int i = 1; i < lastCode + 1; i++)
            {
                writer.WriteLine(i.ToString().PadLeft(padSize, '0'));

                if (i % 100 == 0)
                {
                    Console.WriteLine(i.ToString());
                }
            }

            writer.Close();

            Console.WriteLine();
            Console.WriteLine(lastCode + " codes written to \n" + filename);
            Console.Read();

        }
    }
}