Wyvernity's Enchantment+ Not Working

Are any of you familiar with Wyvernity's Enchantment+ data pack? I tried installing it onto my server but it's only half working for some reason.
Instead of re-explaining everything, I'll just show the message I sent him. He's the creator.
And, full disclosure, I don't make data packs. I'm just trying to install one and it's not working. I hope I can get some help here.
Heres a screenshot of what I told him.