java.lang.IllegalStateException ¿qué significa?

Estoy desarrollando una aplicación de video. Después de la primera reproducción de video, en "OnCopletion" estoy tratando de comenzar una nueva. Pero simplemente se detiene (no se bloquea) y no hace nada. En el registro:java.lang.IllegalStateException ¿qué significa?

10-19 09:44:49.056: ERROR/MediaPlayer(4654): setDataSource called in state 128 
10-19 09:44:49.056: WARN/System.err(4654): java.lang.IllegalStateException 
10-19 09:44:49.056: WARN/System.err(4654):  at android.media.MediaPlayer.setDataSource(Native Method) 
10-19 09:44:49.056: WARN/System.err(4654):  at ru.osiris.BusAdvertising.BusAdvertisingActivity.onCompletion(BusAdvertisingActivity.java:1255) 
10-19 09:44:49.056: WARN/System.err(4654):  at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:1304) 
10-19 09:44:49.056: WARN/System.err(4654):  at android.os.Handler.dispatchMessage(Handler.java:99) 
10-19 09:44:49.056: WARN/System.err(4654):  at android.os.Looper.loop(Looper.java:123) 
10-19 09:44:49.056: WARN/System.err(4654):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
10-19 09:44:49.056: WARN/System.err(4654):  at java.lang.reflect.Method.invokeNative(Native Method) 
10-19 09:44:49.056: WARN/System.err(4654):  at java.lang.reflect.Method.invoke(Method.java:521) 
10-19 09:44:49.056: WARN/System.err(4654):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
10-19 09:44:49.056: WARN/System.err(4654):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
10-19 09:44:49.056: WARN/System.err(4654):  at dalvik.system.NativeStart.main(Native Method)

¿qué significa? ¿Cómo puedo arreglarlo? no es mi código:

public class BusAdvertisingActivity extends Activity implements LocationListener, OnBufferingUpdateListener, OnCompletionListener, 
OnPreparedListener, OnVideoSizeChangedListener, SurfaceHolder.Callback { 
... 
    private MediaPlayer mMediaPlayer; 
    private SurfaceView mPreview; 
    private SurfaceHolder holder; 
    private String path; 
    private Bundle extras; 

    @Override 
    public void onCreate(Bundle icicle) { 
     mPreview = (SurfaceView) findViewById(R.id.surface); 
     holder = mPreview.getHolder(); 
     holder.addCallback(this); 
     holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
     extras = getIntent().getExtras(); 
    } 
public void surfaceCreated(SurfaceHolder holder) { 
     Log.d(TAG, "surfaceCreated called"); 
     playVideo(); 
} 
private void playVideo(Integer Media) { 
     Log.d(TAG, "playVideo called"); 
     doCleanUp(); 
     try { 
      File clip=new File(Environment.getExternalStorageDirectory(), 
          playList[FLcurrentVideo].substring(2,   playList[FLcurrentVideo].length()-1)+".mp4"); 
      path = clip.getAbsolutePath(); 
      mMediaPlayer = new MediaPlayer(); 
      mMediaPlayer.setDataSource(path); 
      mMediaPlayer.setDisplay(holder); 
      mMediaPlayer.prepare(); 
      mMediaPlayer.setOnBufferingUpdateListener(this); 
      mMediaPlayer.setOnCompletionListener(this); 
      mMediaPlayer.setOnPreparedListener(this); 
      mMediaPlayer.setOnVideoSizeChangedListener(this); 
      mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); 


     } catch (Exception e) { 
      Log.e(TAG, "error: " + e.getMessage(), e); 
     } 
    } 


public void onCompletion(MediaPlayer arg0) { 

     Log.d(TAG, "onCompletion called"); 
     FLcurrentVideo++; 

     File clip=new File(Environment.getExternalStorageDirectory(), 
       playList[FLcurrentVideo].substring(2, playList[FLcurrentVideo].length()-1)+".mp4"); 
       path = clip.getAbsolutePath(); 

        try { 
         Log.d ("111", path); 
         arg0.setDataSource(clip.getAbsolutePath()); //I got exception here 
         arg0.setDisplay(holder); 
         arg0.prepare(); 
         arg0.setOnBufferingUpdateListener(this); 
         arg0.setOnCompletionListener(this); 
         arg0.setOnPreparedListener(this); 
         arg0.setOnVideoSizeChangedListener(this); 
         arg0.setAudioStreamType(AudioManager.STREAM_MUSIC); 
        } catch (IllegalArgumentException e) { 
         // TODO Auto-generated catch block 
         e.printStackTrace(); 
        } catch (IllegalStateException e) { 
         // TODO Auto-generated catch block 
         e.printStackTrace(); 
        } catch (IOException e) { 
         // TODO Auto-generated catch block 
         e.printStackTrace(); 
        } 



    }

Por favor, ayúdame.

Fuente

2011-10-19 SentineL