Bing Maps GPXRouteViewerSample won't run - having a debugger attached is unexpected?

When I try to run GPXRouteViewerSample, it stops on this line in App.g.i.cs:

if (Debugger.IsAttached) Debugger.Break();

...and I get the err msg:

Error 1 The specified procedure could not be found. (Exception from HRESULT: 0x8007007F) C:\Users\Clay\Documents\Visual Studio 2012\Samples\bingMapsCSharpGPXRouteViewerSample\GPXRouteViewerSample\MainPage.xaml 12 9 GPXRouteViewerSample

I don't get why they would want it to break if a debugger is attached - IOW, you can't run it from Visual Studio, or..???

MORE INFO

When I open the sample app, the WPF/XAML design surface says, "Cannot create an instance of "Map" But then when I enter my Bing Maps key in the appropriate place (Credentials="") it displays.

Then at runtime, though, when the error occurs on the "debug break" line, the surface/canvas shows that same error. Is it accepting the credentials at design-time but not at runtime?

Here are the details of the exception (this is actually from a different sample (Landmark Events), but I'm sure it's the same problem, as it's dying in the same place):

Exception: Cannot Create an Instance of Map Stack Trace: at Microsoft.Expression.Platform.InstanceBuilders.InstanceBuilderOperations.Instant iateType(Type type, Boolean supportInternal) at Microsoft.Expression.Platform.InstanceBuilders.ClrObjectInstanceBuilder.Instanti ateTargetType(IInstanceBuilderContext context, ViewNode viewNode) at Microsoft.Expression.Platform.InstanceBuilders.ClrObjectInstanceBuilder.Instanti ate(IInstanceBuilderContext context, ViewNode viewNode) at Microsoft.Expression.WindowsXamlPlatform.InstanceBuilders.FrameworkElementInstan ceBuilder.Instantiate(IInstanceBuilderContext context, ViewNode viewNode) at Microsoft.Expression.Platform.InstanceBuilders.ViewNodeManager.CreateInstance (IInstanceBuilder builder, ViewNode viewNode) Inner Exception: TargetInvocationException: Exception has been thrown by the target of an invocation. Stack Trace: at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) COMException: The specified procedure could not be found. (Exception from HRESULT: 0x8007007F)