java.lang.noclassdeffounderror: com.google.android.gms.R$styleable

Я создаю приложение для Android, используя карты Google. вот код:

MapFragActivity.java

 import android.os.Bundle;
    import android.support.v4.app.FragmentActivity;
    import com.google.android.gms.maps.GoogleMap;
    import com.google.android.gms.maps.SupportMapFragment;

    public class MapFragActivity extends FragmentActivity {

    private GoogleMap map;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map_frag);

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

AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.him.mapfrag_rnd"
        android:versionCode="1"
        android:versionName="1.0" >

        <uses-sdk
            android:minSdkVersion="11"
            android:targetSdkVersion="15" />


        <permission
            android:name="com.him.mapfrag_rnd.permission.MAPS_RECEIVE"
            android:protectionLevel="signature" />

        <uses-permission android:name="com.him.mapfrag_rnd.permission.MAPS_RECEIVE" />
        <uses-permission android:name="android.permission.INTERNET" />
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
        <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
        <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />

          <uses-feature
            android:glEsVersion="0x00020000"
            android:required="true" />


        <application
            android:icon="@drawable/ic_launcher"
            android:label="@string/app_name"
            android:theme="@style/AppTheme" >
            <activity
                android:name=".MapFragActivity"
                android:label="@string/title_activity_map_frag" >
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />

                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>

            <meta-data
                android:name="com.google.android.maps.v2.API_KEY"
                android:value="my_api_key" />

        </application>

    </manifest>

activity_map_frag.xml:

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

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

    </RelativeLayout>

когда я пробую этот код, я получаю сообщение об ошибке, вот журнал:

01-17 10:01:17.685: E/AndroidRuntime(8923): FATAL EXCEPTION: main
    01-17 10:01:17.685: E/AndroidRuntime(8923): java.lang.NoClassDefFoundError: com.google.android.gms.R$styleable
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at com.google.android.gms.maps.GoogleMapOptions.createFromAttributes(Unknown Source)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at com.google.android.gms.maps.SupportMapFragment.onInflate(Unknown Source)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:279)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:669)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:739)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:272)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.Activity.setContentView(Activity.java:1835)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at com.him.mapfrag_rnd.MapFragActivity.onCreate(MapFragActivity.java:16)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.Activity.performCreate(Activity.java:4470)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1052)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.ActivityThread.access$600(ActivityThread.java:127)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.os.Handler.dispatchMessage(Handler.java:99)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.os.Looper.loop(Looper.java:137)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at android.app.ActivityThread.main(ActivityThread.java:4511)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at java.lang.reflect.Method.invokeNative(Native Method)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at java.lang.reflect.Method.invoke(Method.java:511)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:986)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:753)
    01-17 10:01:17.685: E/AndroidRuntime(8923):     at dalvik.system.NativeStart.main(Native Method)

когда я делаю некоторые изменения в MapFragActivity.java, отображается карта. вот изменения:

package com.him.mapfrag_rnd;

    import android.os.Bundle;
    import android.support.v4.app.FragmentActivity;

    import com.google.android.gms.maps.SupportMapFragment;

    public class MapFragActivity extends FragmentActivity {

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            //setContentView(R.layout.activity_map_frag);
          SupportMapFragment fragment = new SupportMapFragment();
          getSupportFragmentManager().beginTransaction().add(android.R.id.content, fragment).commit();
        }
    }

Сделанное мной изменение прокомментировано в setContentView. Я выполнил все необходимые шаги, но все равно получаю ошибку. если раскомментировать setContentView(), то я снова получаю сообщение об ошибке.

Пожалуйста помоги!!!