Hi Vortex! The file you are trying to use is not for the RPG_Maker, try using the characters you find here instead: "Modern_Interiors" -> "5_RPG_Makers" -> "RPG_Maker_MV" -> "Characters"!
The "Character generator" folder is not designed to be used in the rpg makers atm cause they require specific sizes and frames numbe, but I can make an Rpg Maker MV version of it if requested!