So he originally wrote it to work with WordPressMU. When that was merged back into the main branch of WP, some of the functions, constants, etc changed. He never updated it to work with it again.
It still works with multisite, but it doesn’t recognize that it is being used on a multisite network. The main thing being that the configuration settings were specific to each individual site. This meant to use it on the entire network, you had to configure it for each individual site…very impractical if you have a lot of sites. It also issued some php errors when trying to find tables that didn’t exist.
I’ve fixed those issues and posted my updated version to GitHub here:
https://github.com/earnjam/active-directory-integration
I’ve also contacted the developer and told him about my updates. I’m waiting to see what he will do with them.
I’m using my version on a network with about 5800 sites and it is working great. I’m going to add another feature this week to give the option to change the Lost Password URL to point to a different location, as that is not managed through WP for us.