Essentials 15 Error when displaying the load game screen

My game was loading fine the other day, I haven't made too many changes, I've mostly been working on sprites, now I receive this error:

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Pokemon Essentials
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Exception: NoMethodError

Message: undefined method `width' for nil:NilClass

PokemonLoad:165:in `pbSetParty'

PokemonLoad:329:in `pbStartLoadScreen'

Main:6:in `main'

Main:51:in `mainFunctionDebug'

Main:29:in `mainFunction'

Main:29:in `pbCriticalCode'

Main:29:in `mainFunction'

Main:61

Main:60:in `loop'

Main:69