[Error] Mathematical operations cause NoMethodErrors

[#Not Important]

I keep getting this sort of errors

[Pokémon Essentials version 18]
Exception: NoMethodError
Message: undefined method `*' for nil:NilClass

Backtrace:
Tilemap_XP:409:in `addTile'
Tilemap_XP:843:in `refresh'
Tilemap_XP:840:in `each'
Tilemap_XP:840:in `refresh'
Tilemap_XP:938:in `update'
TilemapLoader:49:in `update'
Spriteset_Map:130:in `_animationSprite_update'
Sprite_AnimationSprite:89:in `update'
Spriteset_Map:68:in `_animationSprite_initialize'
Sprite_AnimationSprite:50:in `shadow_initialize'

it happens when doing mathematical operations
e.g. +, -, *, /,**, etc.

 

[Turn20Negate]

This error usually happens when you use mathematical operators on Objects that aren't Numerics. So double check each time if you are multiplying numbers.