google map v2 throws no found class error of rstylable

Question

i have successfully followed all the process to start the the google map v2, but at runtime it through class not found error, how to get out of this stuff

here is the xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <fragment

        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        class="com.google.android.gms.maps.SupportMapFragment" />

</RelativeLayout>

here is my code

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;

public class MainActivity extends FragmentActivity {


  private GoogleMap map;

  @Override
  protected void onCreate(Bundle savedInstanceState) 
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_select_location);

    map = ((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map)).getMap();

  }



} 

logcat

02-20 11:44:56.103: E/AndroidRuntime(1394): FATAL EXCEPTION: main
02-20 11:44:56.103: E/AndroidRuntime(1394): java.lang.NoClassDefFoundError: com.google.android.gms.R$styleable
02-20 11:44:56.103: E/AndroidRuntime(1394):     at com.google.android.gms.maps.GoogleMapOptions.createFromAttributes(Unknown Source)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at com.google.android.gms.maps.SupportMapFragment.onInflate(Unknown Source)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:271)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:558)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:618)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.view.LayoutInflater.inflate(LayoutInflater.java:407)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:198)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.Activity.setContentView(Activity.java:1647)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at com.curioussolutions.autoistdiary.MainActivity.onCreate(MainActivity.java:26)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.os.Looper.loop(Looper.java:123)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at android.app.ActivityThread.main(ActivityThread.java:4627)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at java.lang.reflect.Method.invokeNative(Native Method)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at java.lang.reflect.Method.invoke(Method.java:521)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
02-20 11:44:56.103: E/AndroidRuntime(1394):     at dalvik.system.NativeStart.main(Native Method)
02-20 11:44:56.613: W/jdwp(1394): Debugger is telling the VM to exit with code=1

do reply ,thank you