Problem to close Unity Project integrate in Android Activity

Hi All, I follow this guide for integrate one Unity project into an Android Activity. Thanks to a Button I start this Activity and all run very well, I am able to send message from Android to Unity, very cool. The problem is when I try to close this activity using onBackPressed Event. The activity is close but when I try to re-open it I have just a black screen and the unity project isn't create, my Logcat send me this error:

 04-29 11:23:36.305: E/ActivityThread(22316): Activity com.example.footmoov_prove.Avatar has leaked IntentReceiver com.unity3d.player.UnityPlayer$3@41e15558 that was originally registered here. Are you missing a call to unregisterReceiver()?
 04-29 11:23:36.305: E/ActivityThread(22316): android.app.IntentReceiverLeaked: Activity com.example.footmoov_prove.Avatar has leaked IntentReceiver com.unity3d.player.UnityPlayer$3@41e15558 that was originally registered here. Are you missing a call to unregisterReceiver()?
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:792)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:593)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:1254)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ContextImpl.registerReceiver(ContextImpl.java:1241)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ContextImpl.registerReceiver(ContextImpl.java:1235)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:372)
 04-29 11:23:36.305: E/ActivityThread(22316):     at com.unity3d.player.UnityPlayer.<init>(Unknown Source)
 04-29 11:23:36.305: E/ActivityThread(22316):     at com.example.footmoov_prove.Avatar.onCreate(Avatar.java:34)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.Activity.performCreate(Activity.java:5206)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ActivityThread.access$600(ActivityThread.java:140)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.os.Handler.dispatchMessage(Handler.java:99)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.os.Looper.loop(Looper.java:137)
 04-29 11:23:36.305: E/ActivityThread(22316):     at android.app.ActivityThread.main(ActivityThread.java:4898)
 04-29 11:23:36.305: E/ActivityThread(22316):     at java.lang.reflect.Method.invokeNative(Native Method)
 04-29 11:23:36.305: E/ActivityThread(22316):     at java.lang.reflect.Method.invoke(Method.java:511)
 04-29 11:23:36.305: E/ActivityThread(22316):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
 04-29 11:23:36.305: E/ActivityThread(22316):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
 04-29 11:23:36.305: E/ActivityThread(22316):     at dalvik.system.NativeStart.main(Native Method)
 

My Activity code is:

 @Override
     protected void onCreate(Bundle savedInstanceState){
         super.onCreate(savedInstanceState);
         setContentView(R.layout.avatar);
         m_UnityPlayer = new UnityPlayer(this);
         int glesMode = m_UnityPlayer.getSettings().getInt("gles_mode", 1);
         boolean trueColor8888 = false;
         m_UnityPlayer.init(glesMode, trueColor8888);
         
         FrameLayout layout = (FrameLayout) findViewById(R.id.framelayout_avatar);
         LayoutParams lp = new LayoutParams (LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
         layout.addView(m_UnityPlayer.getView(), 0, lp);
 
     }

 

 @Override
     public void onWindowFocusChanged(boolean hasFocus){
         super.onWindowFocusChanged(hasFocus);
         m_UnityPlayer.windowFocusChanged(hasFocus);
     }

 @Override
     public void onBackPressed(){
         LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
         super.onBackPressed();
     }

Other code in the Activity is not important