Problems upgrading .NET remoting services to 4.0 in IIS

Question

I'm trying to upgrade a legacy .NET remoting web services project to .NET 4.0 in IIS7. The old project is currently running fine on 2.0. All of the projects in the solution were upgraded to 4.0, rebuilt and deployed to a new web application running in a 4.0 integrated app pool on a different server. All of the URIs to the services are configured in the web.config using *.rem extensions. Whenever I try to make calls to the services on this new project I am getting server 500 errors complaining that there was a problem with the resource I am trying to access.

When checking the Handler Mappings in IIS for this application, I've notice some strange behavior. Whenever I try to edit the 'HttpRemotingHandlerFactory-rem-Integrated-4.0' handler (which is the one I'm assuming would need to be used given the version and type of app pool I run) I get the following errors:

1) Unrecognized attribute 'targetframework' referring to the 'targetFramework="4.0"' in my web.config

2) If I remove that attribute, then I get the 'The assembly Foo could not be loaded because it was built using a newer framework than the one currently loaded'

Anywhere I've checked says that this means I need to change the app pool to be running on 4.0 instead of 2.0, but it's ALREADY running 4.0! I've checked everywhere I can, I've even changed the Default Web Site to be in a 4.0 app pool as well with no luck. Is there some obscure setting somewhere that I am just missing, or something that I'm not thinking of?

Answer 1

I was able to get past the issue by changing the mode from Integrated to Classic, and running the app pool as myself (to be changed later into a user created specifically for this web app). I still get the error messages when trying to edit the integrated rem handler though, maybe it's just an issue with that particular handler.