deploying WCF rest service in an app domain

I have read the article here and here. I've followed every single step they have there, which is: 1. Add a service.svc to the main folder of my apps domain, which is:

 <%@ ServiceHost Language="C#" Debug="true" Service="RESTServicePublishing.RestService" CodeBehind="RestService.svc.cs" Factory="System.ServiceModel.Activation.WebServiceHostFactory" %>

1. I then added the WcfService1.dll into the bin folder of my app domain
2. The third asked me to specify the endpoint in the web.config, now I am not sure on how to do this part.

When I try to open the site it gives me开发者_运维技巧 this error:

Could not load file or assembly 'WcfService1' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

How can I fix this?