Need help with my script

[Furious^ONE!]

Hello, i have made a script, but he not work, do you have solution please ?

Code:

function headShot(attacker, weapon, bodypart, loss) 
 if (bodypart == 9) then 
  setPedAnimation(source, "KNIFE", "KILL_Knife_Ped_Die") 
  
  end 
end 
addEventHandler("onPlayerDamage", getRootElement(), headShot) 

[LabiVila]

What does debugscript say? It seems fine to me

[Furious^ONE!]

i dont know