Relic Castle

When hatching any egg, the game will crash and present this message:

[Pokémon Essentials version 17.1]
Exception: RuntimeError
Message: filename is nil
SpriteWindow_sprites:30:in `initialize'
PScreen_EggHatching:47:in `new'
PScreen_EggHatching:47:in `pbMain'
PScreen_EggHatching:161:in `pbStartScreen'
PScreen_EggHatching:173:in `pbHatchAnimation'
PScreen_EggHatching:170:in `pbFadeOutInWithMusic'
PSystem_Utilities:142:in `pbFadeOutIn'
PSystem_Utilities:142:in `pbFadeOutInWithMusic'
PScreen_EggHatching:170:in `pbHatchAnimation'
PScreen_EggHatching:191:in `pbHatch'

I do have the needed Egg and Cracks graphics.