Can you make sure the MVC assemblies has been set copy to local
property with "True" in MVC 4 website application? And i'd like to suggest you set debug to ture to collect more information about the exception. The configuration will be like this:
In addition, Do you enable .NET 4.5 or .NET 4.0 for MVC web application? Would you like to check the target frameworks version with web config file?
Yes, As I was mentioned above, 500 error maybe a very
broad error message, we can not make sure where the exception was thrown, so i think you need post them first. The configurations and code looks no propblem.