Question: We are using the beloved Ninject+Ninject.Web.Mvc with MVC 2 and are running into some problems. Specifically dealing with 404 errors. We have a logging service that logs 500 errors and records them. Everything is chugging along just perfectly except for when we attempt to enter a non-existent controller. Instead of getting the desired 404 we end up with a 500 error:

```
Cannot be null
Parameter name: service
[ArgumentNullException: Cannot be null
Parameter name: service]
   Ninject.ResolutionExtensions.GetResolutionIterator(IResolutionRoot root, Type service, Func`2 constraint, IEnumerable`1 parameters, Boolean isOptional) +188
   Ninject.ResolutionExtensions.TryGet(IResolutionRoot root, Type service, IParameter[] parameters) +15
   Ninject.Web.Mvc.NinjectControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +36
   System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +68
   System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +118
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +46
   System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +63
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +13
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8679426
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

```

I did some searching and found some similar issues, but those 404 issues seem to be unrelated. Any help here would be great.

Thanks!
Josh

Answer: 
EDIT: This is in the trunk now for MVC2: <http://github.com/enkari/ninject.web.mvc>

controllerType is coming in null now, we can pass it to the base and let the 404 happen properly:

```
        protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
    {
        if(controllerType == null)
        {
            // let the base handle 404 errors with proper culture information
            return base.GetControllerInstance(requestContext, controllerType);
        }

        var controller = Kernel.TryGet(controllerType) as IController;

        if (controller == null)
            return base.GetControllerInstance(requestContext, controllerType);

        var standardController = controller as Controller;

        if (standardController != null)
            standardController.ActionInvoker = CreateActionInvoker();

        return controller;
    }

```
Needed to modify NinjectControllerFactory.cs source code by adding the 404. I have added the source code for anyone interested in fixing:

```
    protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
    {
        if (controllerType == null)
            throw new HttpException(
                404, String.Format(
                         "The controller for path '{0}' could not be found " +
                         "or it does not implement IController.",
                         requestContext.HttpContext.Request.Path));

        var controller = Kernel.TryGet(controllerType) as IController;

        ...

```