Actually, it's probably because I forgot to update the first post with the fixed version. :s

Sapiento told me of an error with it and I posted a fix for it at the end of the thread but forgot to upload a fixed version at the start. D'oh! I'll update it first thing tomorrow. Sorry.

As a quick fix you can just download the extra zip I posted at the end of the thread and unzip it into your root TreeThing directory.