Exception: WWW download:Unknown Error

I'm getting this error when using WWW.LoadFromCacheOrDownload: on Android

Code (CSharp):

1. Exception: WWW download:Unknown Error

This is the code:

Code (CSharp):

1. // Download an AssetBundle
2.     public static IEnumerator downloadAssetBundle(string url, int version)
3.     {
4.         Debug.Log("We are now going to download... " + url);
5.         Global.Instance.downloadPercentage = 0f;
6.         AssetBundleProgressBar.Instance.Begin();
7.  
8.         string keyName = url + version.ToString();
9.         if (dictAssetBundleRefs.ContainsKey(keyName))
10.             yield return null;
11.         else
12.         {
13.             while (!Caching.ready)
14.                 yield return null;
15.             Debug.Log(url);
16.             using (WWW www = WWW.LoadFromCacheOrDownload(url, version))
17.             {
18.                 // Added code for progress bar
19.                 while (!www.isDone)
20.                 {
21.                     Global.Instance.downloadPercentage = Mathf.Clamp01(www.progress / 0.9f);
22.                     // Debug.Log(www.progress);
23.                     yield return null;
24.                 }
25.                 AssetBundleProgressBar.Instance.End();
26.  
27.                 yield return www;
28.                 if (www.error != null)
29.                     throw new Exception("WWW download:" + www.error);
30.                 AssetBundleRef abRef = new AssetBundleRef(url, version);
31.                 abRef.assetBundle = www.assetBundle;
32.                 dictAssetBundleRefs.Add(keyName, abRef);
33.             }
34.         }
35.     }

It's downloading from here:

http://www.roseportalgames.com/files/assetbundles/Android/duplicates

I didn't have this problem before updating my game with some new content so I'm a bit confused.

Thanks,