NPE when trying to use webwalking with custom web

I'm using @Aidden's tutorial to add a web file I created with Hax's Web Extender to the default web. However, upon trying to webwalk to my destination (Canifis bank), I get a NPE with this line of code:

Traversal.getDefaultWeb().getPathBuilder().buildTo(new Coordinate(3423, 3544, 0)).step();