playSound() throwing NPE

package com.example.crystalball;

import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity {

    private CrystalBall mCrystalBall = new CrystalBall();
    private TextView mAnswerLabel;
    private Button mGetAnswerButton;
    private ImageView mCrystalBallImage;
    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        //Assigning Views from the layout file
        mAnswerLabel = (TextView) findViewById(R.id.textView1);
        mGetAnswerButton = (Button) findViewById(R.id.button1);
        mCrystalBallImage = (ImageView) findViewById(R.id.imageView);

        mGetAnswerButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View arg0) {
                String answer = mCrystalBall.getAnAnswer();

                //Update the label with our dynamic answer


                mAnswerLabel.setText(answer);

                animateCrystalBall();
                animateAnswer();
                playSound();
            }
        });
    }

    private void animateCrystalBall() {
        mCrystalBallImage.setImageResource(R.drawable.ball_animation);
        AnimationDrawable ballAnimation = (AnimationDrawable) mCrystalBallImage.getDrawable();
        if (ballAnimation.isRunning()) {
            ballAnimation.stop();
        }
        ballAnimation.start();
    }

    private void animateAnswer() {
        AlphaAnimation fadeInAnimation = new AlphaAnimation(0, 1);
        fadeInAnimation.setDuration(1500);
        fadeInAnimation.setFillAfter(true);

        mAnswerLabel.setAnimation(fadeInAnimation);
    }

    private void playSound() {
        MediaPlayer player = MediaPlayer.create(this, R.raw.crystal_ball);
        player.start();
        player.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
            public void onCompletion(MediaPlayer mp) {
                mp.release();
            }
        });
    }
}

05-04 14:44:36.987  14944-14944/com.example.crystalball I/dalvikvm-heap? Grow heap (frag case) to 15.194MB for 1825216-byte allocation
05-04 14:44:37.347  14944-14944/com.example.crystalball E/MediaPlayer? Unable to create media player
05-04 14:44:37.357  14944-14944/com.example.crystalball D/MediaPlayer? create failed:
    java.io.IOException: setDataSourceFD failed.: status=0x80000000
            at android.media.MediaPlayer._setDataSource(Native Method)
            at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1282)
            at android.media.MediaPlayer.create(MediaPlayer.java:1006)
            at com.example.crystalball.MainActivity.playSound(MainActivity.java:66)
            at com.example.crystalball.MainActivity.access$400(MainActivity.java:13)
            at com.example.crystalball.MainActivity$1.onClick(MainActivity.java:43)
            at android.view.View.performClick(View.java:4480)
            at android.view.View$PerformClick.run(View.java:18686)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:157)
            at android.app.ActivityThread.main(ActivityThread.java:5872)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:852)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:668)
            at dalvik.system.NativeStart.main(Native Method)
05-04 14:44:37.357  14944-14944/com.example.crystalball W/dalvikvm? threadid=1: thread exiting with uncaught exception (group=0x4170be18)
05-04 14:44:37.357  14944-14944/com.example.crystalball E/AndroidRuntime? FATAL EXCEPTION: main
    Process: com.example.crystalball, PID: 14944
    java.lang.NullPointerException
            at com.example.crystalball.MainActivity.playSound(MainActivity.java:67)
            at com.example.crystalball.MainActivity.access$400(MainActivity.java:13)
            at com.example.crystalball.MainActivity$1.onClick(MainActivity.java:43)
            at android.view.View.performClick(View.java:4480)
            at android.view.View$PerformClick.run(View.java:18686)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:157)
            at android.app.ActivityThread.main(ActivityThread.java:5872)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:852)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:668)
            at dalvik.system.NativeStart.main(Native Method)
05-04 14:44:40.147  14944-14944/com.example.crystalball D/Process? killProcess, pid=14944
05-04 14:44:40.147  14944-14944/com.example.crystalball D/Process? com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException:131 java.lang.ThreadGroup.uncaughtException:693 java.lang.ThreadGroup.uncaughtException:690