MVC is the current buzz in web application architectures. It comes from event-driven desktop application design and doesn't fit into web application design very well. But luckily nobody really knows what MVC means, so we can call our presentation layer separation mechanism MVC and move on. (Rasmus Lerdorf)
Turns out I missed the "on switch" of the program I was trying to run, so that the query it should have made to create the date value to grab never happened. Hence the invalid value.