[ CONSULTA ] Problema: thread exiting with uncaught exception

[LEAJIM_454]

Hola, tengo un problema con nineoldandroids, me da error cuando ejecuto la activity y lo que me dice es esto:
En el log mi app:
[PHP]03-24 20:02:10.091: W/dalvikvm(14727): threadid=15: thread exiting with uncaught exception (group=0x40018578)
[/PHP]
Mi clase java:
[PHP]package com.JimSoft.Edu.LearnWithEnuma;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.ViewTreeObserver.OnGlobalLayoutListen er;
import android.widget.ImageButton;
import android.widget.LinearLayout;

import com.nineoldandroids.animation.ObjectAnimator;

/**
* A simple {@link Fragment} subclass. Activities that contain this fragment
* must implement the {@link MainMenuFragment.OnFragmentInteractionListener}
* interface to handle interaction events. Use the
* {@link MainMenuFragment#newInstance} factory method to create an instance of
* this fragment.
*
*
public class MainMenuFragment extends Fragment implements OnClickListener,OnFragmentInteractionListener, OnGlobalLayoutListener{
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private ObjectAnimator AprendeAlpha1, AprendeAlpha2;



// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private ImageButton btnAprende,btnPractica,btnCuentos;

private View view;
private OnFragmentInteractionListener mListener;

private LinearLayout lytBackGroundAprende;
private LinearLayout txtAprende;


public String VT;
public float HT;
/**
* Use this factory method to create a new instance of this fragment using
* the provided parameters.
*
* @param param1
* Parameter 1.
* @param param2
* Parameter 2.
* @RETURN A new instance of fragment MainMenuFragment.
*
// TODO: Rename and change types and number of parameters
public static MainMenuFragment newInstance(String param1, String param2) {
MainMenuFragment fragment = new MainMenuFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}

public MainMenuFragment() {
// Required empty public constructor
}

@override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}


}

private void onAttach() {
}

@override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
view=inflater.inflate(R.layout.fragment_main_menu, container, false);
lytBackGroundAprende = (LinearLayout)view.findViewById(R.id.LytBackground Aprende);
txtAprende = (LinearLayout)view.findViewById(R.id.TituloAprende );

lytBackGroundAprende.getViewTreeObserver().addOnGl obalLayoutListener(this);
txtAprende.getViewTreeObserver().addOnGlobalLayout Listener(this);

return view;

}
private void AnimacionMaterial1() {
TimerTask Anima1 =new TimerTask() {

@override
public void run() {
AprendeAlpha2 = new ObjectAnimator();
ObjectAnimator.ofFloat(txtAprende, "alpha", 1,0).setDuration(999).start();
AnimacionMaterial2();
}
};
Timer Tim = new Timer();
Tim.schedule(Anima1, 1000);
}
private void AnimacionMaterial2() {
TimerTask Anima2 =new TimerTask() {

@override
public void run() {
AprendeAlpha1 = new ObjectAnimator();
ObjectAnimator.ofFloat(lytBackGroundAprende, "alpha", 0,1).setDuration(999).start();
AnimacionMaterial1();
}
};
Timer Tim = new Timer();
Tim.schedule(Anima2, 1000);
}

// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}

@override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
}

@override
public void onDetach() {
super.onDetach();
mListener = null;
}

@override
public void onClick(View view) {
// TODO Auto-generated method stub
// switch (view.getId()) {
// case R.id.btnAprende:
// FragmentManager fragmentManager =
// getFragmentManager();
// Fragment Fragmentos = null;
// Fragmentos = new PalleteFragment();
// fragmentManager.beginTransaction().replace(R.id.co ntent_frame, Fragmentos).commit();
//
//
// Toast.makeText(getActivity(), VT, Toast.LENGTH_SHORT).show();
// //ObjectAnimator.ofFloat(btnAprende, "rotationY", 0,360).setDuration(500).start();
// break;
/
// default:
// break;
// }
}


@override
public void onFragmentInteraction(Uri uri) {
// TODO Auto-generated method stub

}

@override
public void onGlobalLayout() {
AnimacionMaterial1();

}


}
[/PHP]

Es estas lineas las que causan el error pero no se por que si tienia otra app en las que funcionaban a las mil maravillas por que las coloco como comentario y la app funciona de forma correcta pero no se anima.
[PHP]AprendeAlpha1 = new ObjectAnimator();
ObjectAnimator.ofFloat(lytBackGroundAprende, "alpha", 0,1).setDuration(999).start();[/PHP]

Espero que alguien pueda ayudarme, agradecimientos de antemano y gracias por leer.