I also ran into this same problem, my main.js file in the SERVER folder was wrong.
Even though the docs clearly state that the main.js file needs to be updated, somehow this seems to be a sticking point.... it's probably because there's also main.js file in the CLIENT folder, which makes complete sense. But for whatever reason this seems to be catching people. I glossed over the main.js code because mentally I had "already updated" that file.
As an instructor myself, sometimes I find that I have to update tutorials / materials so that students can get past common snags in the lesson. It would be nice if Meteor put in a small flag to alert people like myself who don't read ( lol ) to be sure to make sure that the client and server side files with the same names are respectively updated with the correct code in each instance.
Overall this is a great tutorial and Meteor is incredibly easy to use and intuitive. Respect to the team.