ARR and MVC3: The virtual path 'null' maps to another application, which is not allowed

I followed Scott Guthrie's suggestion of 开发者_运维知识库trying Microsoft Web Farm Framework, added Application Request Routing, and added an ASP.NET MVC 3 unmodified website. If I remove the inbound rule for IIS's "URL Rewrite", it shows the website. If I add one to redirect the request to the web farm, it gives me a The virtual path 'null' maps to another application, which is not allowed.

What web.config entries or other configuration would I need to get the website to show?

Maybe this can help you: http://lordzoltan.blogspot.com/2010/09/mvc-bug-virtual-path-maps-to-another.html

Do you installed in your machine .Net Framework 4.0?

In Scott example has 2.0.