"Using Ant Tasks" tutorial unclear

I’m working through the user guide and I don’t know how to complete the Using Ant Tasks tutorial. When I run gradle loadfile I receive the following error message:
file("./antLoadfileResources").listFiles() must not be null

I assume that means I’m missing a “antLoadfileResources” file? The page doesn’t seem to mention adding any files and I’m unfamilar with Ant so I don’t know what I’m supposed to do. I think this tutorial could be improved if an example “antLoadfileResources” file is provided so that the loadfile task can actually be executed.

I found a topic created in 2013 that covers this same issue, but I cannot find any potential solutions.