404 Not Found, Problem with WWW:get_assetBundle

hi guys,
I have mac target game and I build assetbundle and it is available in my website in game_files directory, I have this code for download assetbundle to my scene,

using UnityEngine;
using System.Collections;

public class LoadAssets : MonoBehaviour {
	public string URL="http://www.mysite.com/game_files/KSA5.unity3d";

	IEnumerator Start () {
		WWW www = WWW.LoadFromCacheOrDownload(URL,1);
		//wait for download to complete
		yield return www;
		AssetBundle bundle=www.assetBundle;
		GameObject obj = bundle.Load("KSA-Rd-Kgfhd-705",typeof(GameObject)) as GameObject;
	// Update is called once per frame
	void Update () {

I got this error:

You are trying to load data from a www stream which had the following error when downloading.
404 Not Found
<Start>c__Iterator1:MoveNext() (at Assets/Scripts/LoadAssets.cs:11)

However I can read any think from my directory remotely. please some one can give me answer of this problem
… thanks

Not sure why his original answer got deleted. He reposted the answer. I’ve fixed the link in the other answer.

However the linked answer is not a general solution. The error

404 Not found

Is a server side error that indicates that whatever you want to reach though the given URL can’t be found / accessed. Common problems are:

  • wrong URL. Keep in mind that URLs are usually case-sensitive.
  • wrong server settings. The server might not allow a specific file extension to be accessed.

answer is here