I installed Prepro, Libraries, the Github Coffeescript script, and this module.

I set a CS file in my .info file.

I added the following to test:

$ ->
  alert Hello

But whenever I flush caches (I do have Prepro set up to not cache just to test but just to be sure) and view the page, it doesn't seem like anything is processing.

Chrome's console just displays:

Uncaught SyntaxError: Unexpected token >

The source code of the all.coffee file also shows the raw CS code.