I have an MVC4 project with language selection:
1 main part with:
In my case, the same error was not related to Area but thought to post the error caused in my case, which may be helpful for the people who come to this thread by searching "The controller for path was not found or does not implement IController"
The error was caused because of wrong entry in _Layout.cshtml file.
@Styles.Render("~/Content/misc")
The bundle with that name was removed in BundleConfig.cs but forgot to remove it in _Layout.cshtml
It was silly, but we programmers always do lot of silly mistakes :)