Metin2 client loadgame NPC error...plzzz HELP

I try add new mob,and when i put in root-->npc.text 2798 berserker_rpy

and when try login it give me error something like: this loadgame NPC (2798 berserker_rpy) error ..... idk where is problem.....can someone help me plz....thx

anyone help plzz guys...