When using Castle Windsor in web applications you would want to register many of your components with a lifestyle that is associated with a single request. This is the purpose of the PerWebRequest lifestyle.

If you try that with ASP.NET MVC on IIS7, you are likely to receive the following error message:

Looks like you forgot to register the http module Castle.MicroKernel.Lifestyle.PerWebRequestLifestyleModule
Add '<add name="PerRequestLifestyle" type="Castle.MicroKernel.Lifestyle.PerWebRequestLifestyleModule, Castle.MicroKernel" />' to the <httpModules> section on your web.config.

Unfortunately, following the instructions in the error message doesn't help. There's a discussion about this issue on the Castle Project Users forum, but the gist of it is that if you don't need to resolve components during application startup, this shouldn't be an issue, and indeed it isn't – it seems to be something else.

In my case I seem to have solved the problem by registering the HTTP module in configuration/system.webServer/modules instead of configuration/system.web/httpModules.

Although I haven't had the opportunity to dive into the technical details to understand why this works, this seems to solve the problem on both Windows Vista and Windows Server 2008.