I semi-regularly visit the download pages for many mods hosted in the http://files.minecraftforge.net/ repository, often by typing the URL itself. I have noticed that it is case sensitive, as is the rest of http://minecraftforge.net/. As you are using Nginx, I assume that you have simply configured it incorrectly, as opposed to having made a conscience decision to make your website harder to navigate. Here's a Stack Overflow question and answer that should clarify the issue and solution, should you want to make your website case insensitive: http://stackoverflow.com/questions/18415508/how-to-make-url-case-insensitive-with-nginx
I apologize if this isn't the place for this. I couldn't think of anywhere else. ;3
Also, Markus Persson isn't the creator of Minecraft?! Cake!