Initialize Bugsense

App.xaml.cs

public App()
{
     // Standard XAML initialization
     InitializeComponent();

     // Phone-specific initialization
     InitializePhoneApplication();

     // Language display initialization
     InitializeLanguage();

     // Initialize BugSense
     BugSenseHandler.Instance.Init(this, "YOUR_API_KEY");
}

I guess this has changed to BugSenseHandler.Instance.InitAndStartSession(this, "YOUR_API_KEY");