NullPointerException on Render-Collection of common programming errors

when I try to debug this, I got a nullpointerexception. I just don’t get it, something must not been initialized correctly but I can’t see what… Thanks!

@Override
public void create()
{       
    Texture.setEnforcePotImages(false);
    camera = new OrthographicCamera(VIRTUAL_WIDTH, VIRTUAL_HEIGHT);
    camera.setToOrtho(true,VIRTUAL_WIDTH,VIRTUAL_HEIGHT);
    batch = new SpriteBatch();

    labyrinthe = new Labyrinthe(2, VIRTUAL_WIDTH);
    labyrinthe.generer();
    joueur = labyrinthe.getJoueur();
}

@Override
public void dispose()
{
    batch.dispose();
}

@Override
public void render()
{               
    camera.position.set(joueur.getX(), joueur.getY(), 0);
    camera.update();
    camera.apply(Gdx.gl10);

    Gdx.gl.glViewport((int) viewport.x, (int) viewport.y, (int) viewport.width, (int) viewport.height);
    Gdx.gl.glClearColor(1, 1, 1, 1);
    Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

    batch.setProjectionMatrix(camera.combined);
    batch.begin();
    dessinerLabyrinthe();
    dessinerJoueur();
    batch.end(); // Exception on this line
}

Edit : here is the exception :

08-24 09:22:02.413: W/dalvikvm(224): threadid=21: thread exiting with uncaught exception (group=0x4001b188)
08-24 09:22:02.413: E/AndroidRuntime(224): Uncaught handler: thread GLThread exiting due to uncaught exception
08-24 09:22:02.480: E/AndroidRuntime(224): java.lang.NullPointerException
08-24 09:22:02.480: E/AndroidRuntime(224):  at com.badlogic.gdx.graphics.g2d.SpriteBatch.renderMesh(SpriteBatch.java:1042)
08-24 09:22:02.480: E/AndroidRuntime(224):  at com.badlogic.gdx.graphics.g2d.SpriteBatch.end(SpriteBatch.java:269)
08-24 09:22:02.480: E/AndroidRuntime(224):  at com.me.crazymazes.CrazyMazes.render(CrazyMazes.java:60)
08-24 09:22:02.480: E/AndroidRuntime(224):  at com.badlogic.gdx.backends.android.AndroidGraphics.onDrawFrame(AndroidGraphics.java:452)
08-24 09:22:02.480: E/AndroidRuntime(224):  at com.badlogic.gdx.backends.android.surfaceview.GLSurfaceViewCupcake$GLThread.guardedRun(GLSurfaceViewCupcake.java:713)
08-24 09:22:02.480: E/AndroidRuntime(224):  at com.badlogic.gdx.backends.android.surfaceview.GLSurfaceViewCupcake$GLThread.run(GLSurfaceViewCupcake.java:646)

Edit2: Never mind I forgot to call the function that generates the textures…. Thanks anyway