[Error] RELIC SONG ERROR Pokemon Essentials version 18

please Help me
i don't speak english

[Pokémon Essentials version 18]
Exception: NameError
Message: undefined local variable or method `oldForm' for #<PokeBattle_Move_003:0x8640528>

Backtrace:
Move_Effects_000-07F:51:in `pbEndOfMoveUsageEffect'
Battler_UseMove_TriggerEffects:131:in `pbEffectsAfterMove'
Battler_UseMove:505:in `pbUseMove'
Battler_UseMove:59:in `pbProcessTurn'
Battler_UseMove:58:in `logonerr'
Battler_UseMove:58:in `pbProcessTurn'
Battle_Phase_Attack:126:in `pbAttackPhaseMoves'
Battle_Phase_Attack:122:in `each'
Battle_Phase_Attack:122:in `pbAttackPhaseMoves'
Battle_Phase_Attack:108:in `loop'

Looks like an Essentials bug. I reported it on the Bug Reports thread here: https://www.pokecommunity.com/showthread.php?p=10214656#post10214656

I believe to fix it yourself, you need to find this on line 51 of Move_Effects_000-07F:
and replace "oldForm" with "user.form":