Ninject MVC3 – bootstrapper throwing “Already Initialized” exception
Take a look at Setting up a MVC3-application In short: You probably have een App_Start folder in your project with a NinjectMVC3.cs file. When using the NuGet package in combination with modifying the Global.asax (for which there is no reason) you have to remove the App_Start folder and remove the references to WebActivator and Microsoft.Web.Infrastructure