missing ; before statement

I'm running into the following error when trying this example. 

```
uncaught exception: SyntaxError: missing ; before statement
    Evaluating http://localhost:3000/src/main.css
    Error loading http://localhost:3000/src/main.js
```

I'm using JSPM `0.16.2`. 

Would it be an idea to lock the JSPM version by defining it in package.json? 
