Android : Runtime error in GoogleMap app

I am writing an app with GoogleMaps. I run it on emulator now. The layout below works good. I would like to have some additional TextViews and buttons on the screen with the map. But I have runtime error, if I add second TextView or button to my XML. If I add them inside of some LinearLayout, I also get error.

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:background="@color/backNormal"
          android:orientation="vertical"
    >
<TextView
        android:id="@+id/mytext2"
        android:gravity="center"
        android:text='My Text'
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        style="@style/text_style_title"
        />
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="fill_parent"
              android:layout_height="match_parent"
              android:background="@color/backNormal"
              android:orientation="vertical"
        >
    <fragment
            android:id="@+id/map"
            android:name="com.google.android.gms.maps.MapFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
</LinearLayout>

Error text is below:

3459-3459/moorlakgames.packet1 E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: moorlakgames.packet1, PID: 3459
    java.lang.RuntimeException: Unable to start activity ComponentInfo{moorlakgames.packet1/moorlakgames.packet1.MyActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.MapFragment.getMap()' on a null object reference
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.MapFragment.getMap()' on a null object reference

As I said it works with one TextView in layout. Any ideas? Thanks!