This is a mis compatibility with the newest version of the battle core. Pushed an update just now to fix it (v.1.0.1).
For future references of other readers, as of writing:
v.1.0 of this plugin is compatible w/ <= v.1.0.3 of the battle core.
v.1.0.1 of this plugin is compatible w/ >= v.1.0.72 of the battle core.