[Pokémon Essentials version 17.2]
Message: wrong number of arguments(3 for 2)
From what I can gather about this, something isn't loading properly at the start of battle, causing the game to freak out and crash. What I have installed is the entirety of SMPack 2.0 (on this site somewhere), an XY pack I attempted to update myself (though I think that one wasn't more than just some pbs files and images), as well as the EBS (with Utilities added). I'm using 17.2 currently.