Hi!
There is an error happening on EliMz Book ans due to that, The platform plugin is also getting and error.
My guesses are:
- You may be using and old version of EliMZ Book. Try downloading it again on itch io and replace for the plugin you have.
- What RPG Maker version are you using? My plugins that starts with ELIMZ are for Rpg Maker MZ. And those that starts only with Eli_ are for Rpg Maker MV. Make sure you are using the right plugins for the right project.
- Make sure you are using the latest RPG Maker MZ code version.
Check those 3 observations and tell me if they helped you.