Sorry, but occasionally someone will copy a block of code and have no idea about how it shoud be edited
Anyway, I'm probably going to say a couple more obvious things, but: if you see a white page I'd guess that maybe it's hitting that die(). Did you "view source" of the blank page to see if those html comments are there?
Also maybe make sure that the MCAPI.class.php file is in the right place, but I think you'd see an error message if is wasn't.