Updated found leaderboard script to R15 and now broken, please help me understand why?

Hi, me again... every time one of you wonderful people help me I get a little bit closer to not being useless.

My next issue is with a leaderboard script I found that worked but always gave me the following output: Torso is not a valid member of Model

Here is the script (updated to replace Torso with HumanoidRootPart as per my reading on the subject of Torso not being a recognised part of the model):

function onArrival(object)
local player = game.Players:playerFromCharacter(object)
    if player ~= nil then
        local leaderstats = player.leaderstats
        local setlevel = game.Workspace:FindFirstChild(leaderstats.Stage.Value)
        print("gah")
        object.HumanoidRootPart.CFrame = object.HumanoidRootPart.CFrame + Vector3.new(0,3,0)
        wait()
        object.HumanoidRootPart.CFrame = setlevel.CFrame + Vector3.new(0,3,0)
    end
end

function setupBoard(object)
    if object.className == "Player" then
        local addls = Instance.new("IntValue")
        addls.Name = "leaderstats"
        local addstage = Instance.new("IntValue")
        addstage.Name = "Stage"
        addstage.Value = 0
        addstage.Parent = addls
        addls.Parent = object
    end
end

game.Players.PlayerAdded:Connect(setupBoard)
game.Workspace.PlayerAdded:Connect(onArrival)

However, now I get this error: Workspace.Leaderboard:9: attempt to index local 'sl' (a nil value)

If HumanoidRootPart is a valid part of my character I'm not sure why it is breaking the sl variable... any guidance would be great.

Thanks

[edit] During the course of this I found that the above code was outdated and basically broken for my needs... the following is the current working model I'm using:

local datastore = game:GetService("DataStoreService")
local ds1 = datastore:GetDataStore("GemSaveSystem")

game.Players.PlayerAdded:connect(function(plr)
 local folder = Instance.new("Folder", plr)
 folder.Name = "leaderstats"
 local stage = Instance.new("IntValue", folder)
 stage.Name = "Stage"

 stage.Value = ds1:GetAsync(plr.UserId) or 1
 ds1:SetAsync(plr.UserId, stage.Value)

 stage.Changed:connect(function()
  ds1:SetAsync(plr.UserId, stage.Value)
 end)
end)