Asset bundle not getting loaded from cache

In my case instead of simple assetBundles I am dealing with Streamed Scene Asset Bundle.

In my Splash Screen Scene (Before getting in to the actual game) I download the asset bundle using www.loadfromcacheordownload() ....it works fine.

     IEnumerator DownloadAssetBundle(string abname, string url, int version)
     {
         www = WWW.LoadFromCacheOrDownload(url, version);
         
         while (!www.isDone && www.error == null)
         {
             Debug.Log("downloaded " + (www.progress * 100).ToString() + "%..." + "Asset Name : "+abname);
             yield return null;
         }
         
         if ((www.error != null && !www.isDone))
         {
             throw new System.Exception("WWW download had an error:" + www.error);
         }
         else
         {
             yield return www;
         }
     }

Now when my game starts... I ask the user to select from available levels (that were downloaded as asset bundles)....

When I load one of these level ... I again use www.loadfromcacheordownload() .... so this time asset bundle is supposed to be loaded from cache ...

     IEnumerator CreateLevelStringAndLoadLevel(int levelNumber)
     {
         string levelToLoad = "Level_" + levelNumber;
         
         // We have an array of assetbundle info in our jChapterNode, so "chapterNumber - 1" refers to the track number of corresponding assetbundle
         
         string url = GetChapterURL(levelNumber);
         int version = GetChapterVersion(levelNumber);
         
         www = WWW.LoadFromCacheOrDownload(url, version);        // should be loading from cache
         
         //yield return WaitForLoading();
         if(www.error != null)
             throw new UnityException("Error while downloading AssetBundle : " + www.error);
         
         if (Caching.IsVersionCached(url, version))
             bundle = www.assetBundle;
         
         async =  Application.LoadLevelAsync(levelToLoad);                // Level that is to loaded has name Level_1, Level_2....so on...!!    
         
         while (!async.isDone)
         {
             uiSlider.value = async.progress; // Show the progress bar increasing with 'async.progress'
             yield return null;
         }
     }

but my game crashes at this point (on devices) ....and while play testing in editor ... the editor crashes and I am not getting any other leads. No error no exception....nothing...!!

Where can the problem be ... Please help...!!

Cheers....

Thanks in Advance...!!