Good evening I'm having a problem with my Live Wallpaper, the problem is this when rotating the screen shoot me an execution error.

02-24 14:38:37.059: D/GLWallpaperService(3118): onSurfaceDestroyed()
02-24 14:38:37.179: D/GLWallpaperService(3118): onCreate()
02-24 14:38:37.179: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.179: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.179: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.189: D/dalvikvm(3118): GC_FOR_ALLOC freed 582K, 18% free 5850K/7132K, paused 6ms, total 6ms
02-24 14:38:37.189: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.199: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.199: D/dalvikvm(3118): GC_EXPLICIT freed 82K, 18% free 5898K/7132K, paused 0ms+1ms, total 5ms
02-24 14:38:37.209: D/dalvikvm(3118): GC_EXPLICIT freed <1K, 18% free 5898K/7132K, paused 0ms+1ms, total 5ms
02-24 14:38:37.209: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.209: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.219: D/dalvikvm(3118): GC_FOR_ALLOC freed 100K, 16% free 6025K/7132K, paused 3ms, total 3ms
02-24 14:38:37.219: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.219: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.219: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.219: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.219: D/dalvikvm(3118): GC_FOR_ALLOC freed 164K, 17% free 6154K/7336K, paused 3ms, total 3ms
02-24 14:38:37.219: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.219: I/jPCT-AE(3118): Loading Texture...
02-24 14:38:37.229: I/jPCT-AE(3118): Texture loaded...65536 bytes/128*128 pixels!
02-24 14:38:37.279: D/GLWallpaperService(3118): onSurfaceCreated()
02-24 14:38:37.279: I/jPCT-AE(3118): GL context is -1288267568
02-24 14:38:37.279: I/jPCT-AE(3118): OpenGL vendor:     Android
02-24 14:38:37.279: I/jPCT-AE(3118): OpenGL renderer:   Android PixelFlinger 1.4
02-24 14:38:37.279: I/jPCT-AE(3118): OpenGL version:    OpenGL ES-CM 1.0
02-24 14:38:37.279: I/jPCT-AE(3118): OpenGL renderer initialized (using 2/2 texture stages)
02-24 14:38:37.279: W/dalvikvm(3118): threadid=11: thread exiting with uncaught exception (group=0xb2f52648)
02-24 14:38:37.279: E/AndroidRuntime(3118): FATAL EXCEPTION: GLThread 188
02-24 14:38:37.279: E/AndroidRuntime(3118): java.lang.NullPointerException
02-24 14:38:37.279: E/AndroidRuntime(3118): at com.AppEnjoy.SpeakerLiveWallpaper3DFree.MyWallpaperService$MyRenderer.rotarObjeto(MyWallpaperService.java:365)
02-24 14:38:37.279: E/AndroidRuntime(3118): at com.AppEnjoy.SpeakerLiveWallpaper3DFree.MyWallpaperService$MyRenderer.onDrawFrame(MyWallpaperService.java:264)
02-24 14:38:37.279: E/AndroidRuntime(3118): at net.rbgrn.android.glwallpaperservice.GLThread.guardedRun(GLWallpaperService.java:716)
02-24 14:38:37.279: E/AndroidRuntime(3118): at net.rbgrn.android.glwallpaperservice.GLThread.run(GLWallpaperService.java:574)
according to this Live Wallpaper is destroyed and recreated another when you have to load the models supposed to do it but I want to rotate the long Object3D java.lang.NullPointerException error

Here I load the code where the models. and where broken waiting. Any advice on how to perform the load or which load models. From already thank you

Code load model:
public void onSurfaceChanged(GL10 gl, int w, int h) {
if (fb != null) {
fb.dispose();
}
fb = new FrameBuffer(gl, w, h);

world = new World();
world.setAmbientLight(20, 20, 20);

sun = new Light(world);
sun.setIntensity(250, 250, 250);

TextureManager.getInstance().addTexture("texture", texFuego);

cube = Object3D.mergeAll(Loader.load3DS(getResources().getAssets().open("modelos/parlante1.3ds"), 1));
cube.build();
cube.strip();
cube.forceGeometryIndices(true);
cube.rotateZ(-1.5f);

world.removeAllObjects();
world.addObject(cube);


Camera cam = world.getCamera();
cam.moveCamera(Camera.CAMERA_MOVEOUT, 50);
cam.lookAt(cube.getTransformedCenter());


SimpleVector pos = new SimpleVector(0, 0, 15);
part = new ParticleSystem(world, pos, 30, 30, "texture", 20,1, 10, 0);
part.SetMaxScale(4f);
part.setMaxDir(new SimpleVector(0.1f, 1f, 0.1f));


SimpleVector sv = new SimpleVector();
sv.set(cube.getTransformedCenter());
sv.y -= 100;
sv.z -= 100;
sun.setPosition(sv);
MemoryHelper.compact();

if (master == null) {
Logger.log("Saving master Activity!");
master = MyWallpaperService.this;
}

}
Drawing code:

public void onDrawFrame(GL10 gl) {
// (int)(Math.random() * (9-1)+1)

long endTime = System.currentTimeMillis();
float timeDiff = (endTime - startTime) / 1000.0f;
startTime = endTime;

fb.clear(new RGBColor(255, 255, 255));

rotarObjeto(cube, rotacion);


world.renderScene(fb);
world.draw(fb);

//particleSystem
part.Update(timeDiff);

fb.display();

}

public void rotarObjeto(Object3D objeto, int Num) {
objeto.rotateX(0);
objeto.rotateY(0);
objeto.rotateZ(0);

if (contador > 63 || contador == 0) {
rotacion = (byte) (Math.random() * (9 - 1) + 1);
contador = 0;
}
contador++;

float Speed = 0.1f;
switch (Num) {
case 1:
objeto.rotateX(Speed);
break;
case 2:
objeto.rotateY(Speed);
break;
case 3:
objeto.rotateZ(Speed);
break;
case 4:
objeto.rotateX(Speed);
break;
case 5:
objeto.rotateY(Speed);
break;
case 6:
objeto.rotateZ(Speed);
break;
case 7:
objeto.rotateX(Speed);
objeto.rotateY(Speed);
break;
case 8:
objeto.rotateX(Speed);
objeto.rotateZ(Speed);
break;
case 9:
objeto.rotateY(Speed);
objeto.rotateZ(Speed);
break;
}
}



It works rather than to start running the problem arises when I turn the screen from portrait to landscape and viceverza