Why do I keep getting "attempt to index field 'Parent' (a nil value)"?

This script performs a points on kill reward. Somewhere after the (-3) test i get an 'attempt to index field 'Parent' (a nil value)' error and I have no idea how to fix it.

  StatName = "Points"
  IncreaseValue = 20
    print("-1")--test
local Humanoid = script.Parent.Humanoid
    print("-2")--test
function Killed()
    print("-3")--test
local tag = Humanoid:findFirstChild("creator")
if tag ~= nil then
    print("*4")--test
    if tag.Value ~= nil then
        print("1")--test
        local Leaderstats = tag.Value:findFirstChild("leaderstats")
        if Leaderstats ~= nil then
        Leaderstats[StatName].Value = Leaderstats[StatName].Value + IncreaseValue
        print("2")--test
        wait(0.1)
        print("3")--test
        end

    end

end
end
Humanoid.Died:connect(Killed)