Can't add google ads

When i run my unity3d apps in visual studio for windows phone with google ads it's not working, because some exception happens:
"Exception type System.UnauthorizedAccessException in System.Windows.ni.dll ..
"Exception type System.UnauthorizedAccessException in Microsoft.Phone.Interop.ni.dll
"Exception type System.Reflection.TargetInvocationException in mscorlib.ni.dll
"Exception type System.IO.FileNotFoundException in mscorlib.ni.dll
"Exception type MS.Internal.NativeParseException in System.Windows.ni.dll

MainPage.xaml.cs

var bridge = new UnityBridge();
Grid ContentPanel;
UnityApp.SetBridge(bridge);
InitializeComponent();
// NOTE: Edit "MY_AD_UNIT_ID" with your ad unit id.
AdView bannerAd = new AdView
{
Format = AdFormats.Banner,
AdUnitID = "ca-app-pub-xxxxx/xxxx"
};
bannerAd.ReceivedAd += OnAdReceived;
bannerAd.FailedToReceiveAd += OnFailedToReceiveAd;
ContentL.Children.Add(bannerAd);
AdRequest adRequest = new AdRequest();
adRequest.ForceTesting = false;
bannerAd.LoadAd(adRequest);
bridge.Control = DrawingSurfaceBackground;

MainPage.xaml is
<DrawingSurfaceBackgroundGrid x:Name="DrawingSurfaceBackground" Loaded="DrawingSurfaceBackground_Loaded">
<GoogleAds:AdView HorizontalAlignment="Left" Margin="27,688,0,0" VerticalAlignment="Top"/>
<GoogleAds:AdView HorizontalAlignment="Left" Margin="48,542,0,0" VerticalAlignment="Top"/>
<Grid Name="ContentL" />
</DrawingSurfaceBackgroundGrid>

What code are needs in MainPage.xaml? or some other features?