Counting monster kills

[selenir]

Hi!
I'm trying to make a script counting how many times i killed for example Rotworm
I was trying to remake few task scripts from forums but unsuccesfully

Here's my script, hope u can help me

function onKill(cid, target)

local StorageValue = 40001
local Creature = "Rotworm" 
local CreaturesKilled = getPlayerStorageValue(cid, StorageValue)

    if CreaturesKilled < 0 then
		setPlayerStorageValue(cid, StorageValue, 0)
	end
	if getCreatureName(target) == Creature then
        setPlayerStorageValue(cid, StorageValue, CreaturesKilled + 1)
    else
		return false
    end

return true
end

 

[Mooosie]

http://otland.net/f82/1-task-npc-rare-129453/