I had the same problem, I fixed it by deleting "m_width, " from line 134 inside the Name Tags + Advanced Portraits.rb file.
Not sure if that's gonna break something down the line but for now it seems to work.
Yeah, so the name windows don't work.
When I try to use the \xn[Name] command i get the following error message:
I tested on a clean copy of Essentials v21.1 and it's giving me the same error.