[Error] Error before the trainer could appear to throw a Pokéball

[JoePikaFireGreen]

I hate to be the one to ask, usually I search for already asked questions, but it seems that nobody did run into this problem before...
In RPG Maker XP Whenever I have an encounter or a trainer challenge, before I could throw the pokéball for my Pokémon to get out and battle I get this error:

[Pokémon Essentials version 19.1]

Exception: NoMethodError
Message: undefined method `width' for nil:NilClass

Backtrace:
192:PokeBattle_Animation:103:in `ballTracksHand'
193:PokeBattle_SceneAnimations:446:in `createProcesses'
192:PokeBattle_Animation:9:in `initialize'
193:PokeBattle_SceneAnimations:416:in `initialize'
200:Scene_Animations:107:in `new'
200:Scene_Animations:107:in `block in pbSendOutBattlers'
200:Scene_Animations:98:in `each'
200:Scene_Animations:98:in `each_with_index'
200:Scene_Animations:98:in `pbSendOutBattlers'
175:Battle_Action_Switching:298:in `pbSendOut'

and also I tried the Safari Zone and when I pressed on the safari ball this same error appeared

I tried hard to find a solution on my own, but this is the case, and I want to continue making the game I am trying to do.

 

[Atlat]

Do you have a back sprite for your trainer? If not, then that is most likely your solution. That's what I did to fix my version of the error.

 

[JoePikaFireGreen]

Oh I'm sorry, I solved the problem long ago, it's was the trainer type, I've made a new trainer and trainer type and replaced Trainer with Gamer, and that was the problem... Now I kept the trainer type as trainer and only changed the display photos and sprites of Red...
And yes, it was the back sprite, but in my case I didn't know how to assign the photo or what to name it in order to work with the trainer type Gamer.
Thank you so much