달력을 실행할 액티비티입니다.

Intent intent = new Intent(net.this, Tab1.class); 
startActivity(intent); 

인텐트를 통해서 액티비티를 실행하려는데요...
혹시나해서 간단하게 반든 다른 액티비티로 인텐트했을때는 잘 실행이 되는데,
이 액티비티에서는 유독 멈추네요...ㅜㅜ
무슨 문제일까요?

내일까지는 해결해야해서 마음이 좀 급하네요..ㅜㅜ
부탁드리겠습니다^^

package my.net;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.TextView;
public class Tab1 extends Activity {
 
 CalendarMonthView monthView;
 CalendarMonthAdapter monthViewAdapter;
 
 TextView monthText;
 
 int curYear;
 int curMonth;
 
 /** Called when the activity is first created. */
 @Override
 
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main2);
     
     monthView = (CalendarMonthView) findViewById(R.id.monthView);
        monthViewAdapter = new CalendarMonthAdapter(this);
        monthView.setAdapter(monthViewAdapter);
        
        // set listener
        monthView.setOnDataSelectionListener(new OnDataSelectionListener() {
   @SuppressWarnings("unchecked")
   public void onDataSelected(AdapterView parent, View v, int position, long id) {
    MonthItem curItem = (MonthItem) monthViewAdapter.getItem(position);
    int day = curItem.getDay();
    
    //Toast.makeText(getApplicationContext(), "Selected : " + day, 1000).show();
    Log.d("CalendarMonthViewActivity", "Selected : " + day);
  
   }
  });
        monthText = (TextView) findViewById(R.id.monthText);
        setMonthText();
        
        Button monthPrevious = (Button) findViewById(R.id.monthPrevious);
        monthPrevious.setOnClickListener(new OnClickListener() {
         public void onClick(View v) {
          monthViewAdapter.setPreviousMonth();
          monthViewAdapter.notifyDataSetChanged();
          
          setMonthText();
         }
        });
        
        Button monthNext = (Button) findViewById(R.id.monthNext);
        monthNext.setOnClickListener(new OnClickListener() {
         public void onClick(View v) {
          monthViewAdapter.setNextMonth();
          monthViewAdapter.notifyDataSetChanged();
          
          setMonthText();
         }
        });
    }
    
    private void setMonthText() {
     curYear = monthViewAdapter.getCurYear();
        curMonth = monthViewAdapter.getCurMonth();
        
        monthText.setText(curYear + "년 " + (curMonth+1) + "월");
    }
}