Why is my self hosted Web API service throwing an exception on Windows 2012? - .net-4.5

Question

I have an app. I'm working on which self-hosts WebApi. It can run as either a command-line app, or as a Windows service. It's compiled using the .NET 4.5 runtimes.
When I run it on my Windows 7 dev. machine, it works fine.
When I deploy and run as a command-line app on my Windows 2012 server machine, it fails with the exception:
Exception has been thrown by the target of an invocation.
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments,
Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Objec
t[] parameters, Object[] arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invoke
Attr, Binder binder, Object[] parameters, CultureInfo culture)
at Owin.Loader.DefaultLoader.<>c__DisplayClass12.<MakeDelegate>b__b(IAppBuild
er builder)
at Owin.Loader.DefaultLoader.<>c__DisplayClass1.<LoadImplementation>b__0(IApp
Builder builder)
at Microsoft.Owin.Hosting.Engine.HostingEngine.ResolveApp(StartContext contex
t)
at Microsoft.Owin.Hosting.Engine.HostingEngine.Start(StartContext context)
at Microsoft.Owin.Hosting.Starter.DirectHostingStarter.Start(StartOptions opt
ions)
at Microsoft.Owin.Hosting.Starter.HostingStarter.Start(StartOptions options)
at Microsoft.Owin.Hosting.WebApp.StartImplementation(IServiceProvider service
s, StartOptions options)
at Microsoft.Owin.Hosting.WebApp.Start(StartOptions options)
at Microsoft.Owin.Hosting.WebApp.Start[TStartup](StartOptions options)
My code does this:
url = "http://localhost:5000";
_app = WebApp.Start<WebAppConfiguration>(url);
And the WebAppConfiguration class looks like this:
public class WebAppConfiguration : HttpConfiguration
{
public void Configuration(IAppBuilders app)
{
ConfigureRoutes();
ConfigureJsonSerialization();
// This line throws the exception:
app.UseWebApi(this);
}
}
I did some searching and it sounded like I needed to reserve the port using NETSH, so this is what I did from an Admin command prompt:
netsh http add urlacl url=http://localhost:5000/ user=Everyone listen=yes delegate=yes
Unfortunately, I'm still getting the exception. Is there some other step I need to do to get this to work under Windows Server 2012?
EDIT:
The inner exception (which I didn't think to log) contained a much more helpful error. It turns out I was missing an assembly binding entry for Microsoft.Owin in my .config file for Owin. This was in my dev. version but didn't make it into the version on my server.