I bought an old book on OS X Carbon once. It lead me down the rabbit hole of code archaeology, where you try to go back in time, collect things, and build something that was. You’re always missing something. Looking at GreenNeon on Cuis is sort of like that. Set the time machine for 2013.
tl;dr - You need a working WebClient for Cuis. The one I used  is not available. I’ve added one from garduino  that informs the Test Runner it has 50 failed tests.
The image I built is long gone. Here’s is the latest Cuis (4.2, released 2013) with garduino’s Networking code, his WebClient, and my GreenNeon.  There are a few useful snippets in the Workspace. I think that if WebClient worked, then so would GreenNeon. But I’m not about to try and debug WebClient on Cuis. Your best bet might be to contact David Graham for his WebClient code.