Facebook Login page doesn't show up

i am using facebook sdk 3.0 ,and i m following the tutorial https://developers.facebook.com/docs/tutorials/androidsdk/3.0/scrumptious/authenticate/ her is the code i am using

my code includes a button clicking on which it should show the facebook page to authenticate the user but on clicking the button it only shows the spinning bar and exits

package com.example.fblogin;

import com.facebook.Session;
import com.facebook.SessionState;
import com.facebook.UiLifecycleHelper;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.Menu;

public class MainActivity extends FragmentActivity {
private static final int SPLASH = 0;
private static final int SELECTION = 1;
private static final int FRAGMENT_COUNT = SELECTION +1;
private boolean isResumed = false;
private UiLifecycleHelper uiHelper;
private Session.StatusCallback callback = 
    new Session.StatusCallback() {
    @Override
    public void call(Session session, 
            SessionState state, Exception exception) {
        onSessionStateChange(session, state, exception);
    }
};




private Fragment[] fragments = new Fragment[FRAGMENT_COUNT];
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    uiHelper = new UiLifecycleHelper(this, callback);
    uiHelper.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    FragmentManager fm = getSupportFragmentManager();
    fragments[SPLASH] = fm.findFragmentById(R.id.splashFragment);
    fragments[SELECTION] = fm.findFragmentById(R.id.selectionFragment);

    FragmentTransaction transaction = fm.beginTransaction();
    for(int i = 0; i < fragments.length; i++) {
        transaction.hide(fragments[i]);
    }
    transaction.commit();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

private void showFragment(int fragmentIndex, boolean addToBackStack) {
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction transaction = fm.beginTransaction();
    for (int i = 0; i < fragments.length; i++) {
        if (i == fragmentIndex) {
            transaction.show(fragments[i]);
        } else {
            transaction.hide(fragments[i]);
        }
    }
    if (addToBackStack) {
        transaction.addToBackStack(null);
    }
    transaction.commit();
}


@Override
public void onResume() {
    super.onResume();
    uiHelper.onResume();
    isResumed = true;
}

@Override
public void onPause() {
    super.onPause();
    uiHelper.onPause();
    isResumed = false;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    uiHelper.onActivityResult(requestCode, resultCode, data);
}

@Override
public void onDestroy() {
    super.onDestroy();
    uiHelper.onDestroy();
}

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    uiHelper.onSaveInstanceState(outState);
}
private void onSessionStateChange(Session session, SessionState state, Exception exception) {
    // Only make changes if the activity is visible
    if (isResumed) {
        FragmentManager manager = getSupportFragmentManager();
        // Get the number of entries in the back stack
        int backStackSize = manager.getBackStackEntryCount();
        // Clear the back stack
        for (int i = 0; i < backStackSize; i++) {
            manager.popBackStack();
        }
        if (state.isOpened()) {
            // If the session state is open:
            // Show the authenticated fragment
            showFragment(SELECTION, false);
        } else if (state.isClosed()) {
            // If the session state is closed:
            // Show the login fragment
            showFragment(SPLASH, false);
        }
    }
}


@Override
protected void onResumeFragments() {
    super.onResumeFragments();
    Session session = Session.getActiveSession();

    if (session != null && session.isOpened()) {
        // if the session is already open,
        // try to show the selection fragment
        showFragment(SELECTION, false);
    } else {
        // otherwise present the splash screen
        // and ask the user to login.
        showFragment(SPLASH, false);
    }
}
}

here is the logcat data

04-08 15:43:05.164: D/dalvikvm(897): GC_CONCURRENT freed 106K, 8% free 2694K/2920K, paused 11ms+4ms, total 105ms
04-08 15:43:05.433: D/gralloc_goldfish(897): Emulator without GPU emulation detected.
04-08 15:43:12.383: D/dalvikvm(897): GC_FOR_ALLOC freed 145K, 9% free 2895K/3164K, paused 80ms, total 88ms
04-08 15:43:12.413: I/dalvikvm-heap(897): Grow heap (frag case) to 3.548MB for 635812-byte allocation
04-08 15:43:12.523: D/dalvikvm(897): GC_FOR_ALLOC freed 2K, 8% free 3513K/3788K, paused 104ms, total 104ms
04-08 15:43:12.683: D/dalvikvm(897): GC_CONCURRENT freed 4K, 8% free 3519K/3788K, paused 9ms+4ms, total 162ms
04-08 15:43:12.983: I/Choreographer(897): Skipped 431 frames!  The application may be doing too much work on its main thread.
04-08 15:43:13.383: I/Choreographer(897): Skipped 51 frames!  The application may be doing too much work on its main thread.
04-08 15:43:15.133: D/FacebookSDK.WebDialog(897): Webview loading URL: https://m.facebook.com/dialog/oauth?type=user_agent&redirect_uri=fbconnect%3A%2F%2Fsuccess&display=touch&client_id=153791708115302
04-08 15:43:15.343: D/dalvikvm(897): GC_CONCURRENT freed 127K, 7% free 3867K/4120K, paused 18ms+18ms, total 102ms
04-08 15:43:15.403: I/Choreographer(897): Skipped 70 frames!  The application may be doing too much work on its main thread.
04-08 15:43:15.563: I/Choreographer(897): Skipped 34 frames!  The application may be doing too much work on its main thread.
04-08 15:43:18.483: A/libc(897): Fatal signal 11 (SIGSEGV) at 0x00000120 (code=1), thread 914 (CookieSyncManag)