Games : My program works in simulation but fails in game mode

I've set up my code so that my main module consists of only the following:

var main = require('main2');

main();

This works in simulation's survival training mode, where main is a function. However, in the online survival mode I have started getting the following error:

main:3
main();
^
TypeError: object is not a function
    at main:3:1
    at process.emit (events.js:110:17)

Why have I started getting this error in the online survival mode?