How to get node asset_builder working with current express?

I've been trying to use the asset_builder node module with express 3.1, but can't seem to make it very far in the setup before receiving an error like this upon starting the server:

var parsed_url = url.parse(request.url);                      
TypeError: Cannot read property 'url' of undefined

This is being thrown from within the middleware.js file of the asset_builder module itself. I'm guessing this is due to the fact that Express apps no longer extend server, and so the setup in the base (app.js) file is a bit different than it once was.

Ideally I'm just trying to use asset_builder to grab all my javascript and serve it as a single file rather than the many I currently have (Ember app).

The base project I'm working off of uses ejs as the express view engine (instead of the default Jade).