Jade + Heroku Internal Server Error

[Stankerne]

Hi,
I followed the Heroku step by step example using :
Plateform: Node,
FrameWork: Express,
CSS FrameWork: none,
CSS Preprocessor: Stylus,
Javascript Framework: none,
Template engine: Jade,
Build tool: npm,
Unit Testing: mocha
Database: none,
Deployement: Heroku

However, after launching the command git push heroku master ( and obviously after login... ), the https://test.herokuapp.com/ throw me an Internal Server Error.
Is there something changed recently?

Thanks!