I have just updated meteor and i am getting this error. As a result,the error is not known to heroku and the app just fails but in my ubuntu installation,it works
=> Started proxy.
=> Started MongoDB.
I20160728-13:13:17.944(3)? { [Error: Cannot find module '../build/Release/bson'] code: 'MODULE_NOT_FOUND' }
W20160728-13:13:18.671(3)? (STDERR) js-bson: Failed to load c++ bson extension, using pure JS version
=> Started your app.
=> App running at: http://localhost:3000/
$ meteor
=> Started proxy.
=> Started MongoDB.
W20160802-13:35:41.552(3)? (STDERR) js-bson: Failed to load c++ bson extension, using pure JS version
=> Started your app.
=> App running at: http://localhost:3000/
I too have the same problem. Just as the OP, the apps works locally (ubuntu) but does not when I deploy to DigitalOcean using MUPX.
=> Started proxy.
=> Started MongoDB.
=> Meteor 1.4.0.1 is available. Update this project with 'meteor update'.
I20160802-14:05:48.607(1)? { [Error: Cannot find module '../build/Release/bson'] code: 'MODULE_NOT_FOUND' }
W20160802-14:05:49.084(1)? (STDERR) js-bson: Failed to load c++ bson extension, using pure JS version
=> Started your app.
=> App running at: http://localhost:3000/