Ah, yeah, it's been long enough since I used j2a-extract that I'd forgotten it wants a palette file. I've put that in the zip too.

You'll probably still have trouble with plus.j2a, but the other two .j2a files in your folder should work fine. FawFul noticed earlier that plus.j2a was accidentally assembled in a way that JJ2+ accepts but j2a-extract doesn't