Scripting error message

Im using the following script to extract the dataset from the OBB files:

 using UnityEngine;
 using System.Collections;
 using System.IO;
 
 public class ObbExtractor : MonoBehaviour {
       
     void Start () {
         StartCoroutine(ExtractObbDatasets());
     }
     private IEnumerator ExtractObbDatasets () {
         string[] filesInOBB = {"tracker.dat", "tracker.xml"};
         foreach (var filename in filesInOBB) {
             string uri = Application.streamingAssetsPath + "/QCAR/" + filename;
             
             string outputFilePath = Application.persistentDataPath + "/QCAR/" + filename;
             if(!Directory.Exists(Path.GetDirectoryName(outputFilePath)))
                 Directory.CreateDirectory(Path.GetDirectoryName(outputFilePath));
             
             var www = new WWW(uri);
             yield return www;
             
             Save(www, outputFilePath);
             yield return new WaitForEndOfFrame();
         }
         
         // When done extracting the datasets, Start Vuforia AR scene
         //Application.LoadLevel("ARScene");
     }
     private void Save(WWW www, string outputPath) {
         File.WriteAllBytes(outputPath, www.bytes);
         
         // Verify that the File has been actually stored
         if(File.Exists(outputPath))
             Debug.Log("File successfully saved at: " + outputPath);
         else
             Debug.Log("Failure!! - File does not exist at: " + outputPath);
 
         Application.LoadLevel("SceneMenu1");
     }
 }

When I Build and Run onto the tablet, all works fine; the obb downloads, it pushes through to an empty scene that extracts the dataset, then it automatically loads the AR scene, augmenting a simple cube.

However, when I put this through Google Developer Console (in Alpha Testing and waiting to propagate) it does all the same but when it reaches the AR scene, it doesn't augment anything.

When I run it in the Editor, I get the following error:

You are trying to load data from a www stream which had the following error when downloading. malformed UnityEngine.WWW:get_bytes() ObbExtractor:Save(WWW, String) (at Assets/ObbExtractor.cs:34) c__Iterator1:MoveNext() (at Assets/ObbExtractor.cs:25)

Does anyone know what the problem could be?

I'm working on the newest versions of Unity and Vuforia and started with a new project, following the tutorial found here: http://www.exoa.fr/tutorial-unity-4-apk-splitting-google-play-obb/#comment-180