All we get when publishing our ASP.Net MVC 3 app is this:

You may also relive the error here.
There’s no error message or anything. We’ve seen this once before, when the connection-string was invalid. This time however, we’re sure that is not the problem.
How should we procceed to “debug” this app? It works fine on the dev server.
I’m seeing the following error when I visit the link you provided:
This error indicates that you do not have MVC 3 installed on the target server and did not deploy the right set of binaries with your app. Read the following for more information: http://weblogs.asp.net/scottgu/archive/2011/01/18/running-an-asp-net-mvc-3-app-on-a-web-server-that-doesn-t-have-asp-net-mvc-3-installed.aspx
(Btw, is your app doing localization, different response encodign, etc? maybe that’s why you are seeing these garbled responses).