DNN 5.01 Internal Server Error 500 with .NET Framework 4.0

I have a DNN 5.01 installation and upgraded the server so it used .NET Framework 4.0 as i wanted i wa开发者_开发知识库nted to get a DNN module working on a portal.

The problem is when i change the application pool for that that installation to use .net 4 the site comes up with a generic error 500 internal server error.

IF i select .net version 2.0 the site works again.

I am also getting errors like these when i double click on icons such as "Error Pages" in IIS 7.5.

My web.config file is below:

enter link description here

edit:

The updated web.config seems to allow the site to work under .net 4 but the login controls dont show up! :(

updated webconfig file