Tengo problemas para ejecutar la demostración de la utilidad API de Android de Google Maps, muestra este error:

04-03 16:32:37.397: E/dalvikvm(2592): Could not find class 'com.google.maps.android.utils.demo.ClusteringDemoActivity', referenced from method com.google.maps.android.utils.demo.MainActivity.onCreate
    04-03 16:32:37.452: E/AndroidRuntime(2592): FATAL EXCEPTION: main
    04-03 16:32:37.452: E/AndroidRuntime(2592): java.lang.NoClassDefFoundError: com.google.maps.android.utils.demo.ClusteringDemoActivity
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at com.google.maps.android.utils.demo.MainActivity.onCreate(MainActivity.java:20)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.Activity.performCreate(Activity.java:5163)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2061)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.ActivityThread.access$600(ActivityThread.java:140)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.os.Handler.dispatchMessage(Handler.java:99)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.os.Looper.loop(Looper.java:137)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at android.app.ActivityThread.main(ActivityThread.java:4895)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at java.lang.reflect.Method.invokeNative(Native Method)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at java.lang.reflect.Method.invoke(Method.java:511)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
    04-03 16:32:37.452: E/AndroidRuntime(2592):     at dalvik.system.NativeStart.main(Native Method)

aunque seguí los pasos que se muestran en la demostración de instalación y la claseClusteringDemoActivity existe en el paquete.