I followed the developer guides on the Android website. It is working fine for a Hello World application but when I try and transition between Activities, my application keeps giving an "The application () has stopped unexpectedly. Please try again later." error and the application then quits. This happens when I click the button in the Subscribe Activity.
Subscribe.java
public class Subscribe extends Activity
implements OnClickListener {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.subscribe);
    Button subButton = (Button)findViewById(R.id.subscribe);
    subButton.setOnClickListener(this);
}
public void onClick(View v) {
    Intent subIntent = new Intent(Subscribe.this,Subscribed.class);
    startActivity(subIntent);
    }
}
Subscribed.java
public class Subscribed extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.subscribed);
 }
}