Entities dissapear when entering level editor again![LOCKED]

[Radical Batz]

This is weird, is it supposed to happen?

I am making a mod and I am loading an entity which are a chest of drawers_alt from mfp and I'm getting them from my entities folder of my FULL CONVERSION MOD

and everytime I re enter the level editor into the map it says "Found some errors while loading file. Check log for details. File index is out of bounds!"

Are you supposed to put that entity in the original entities folder too for it to work? I thought you can just get them from your full conversion mod only and it works, but nope :/