Why does this value not save [DataStore]?

local DataStore = game:GetService("DataStoreService")
local grandopeningkitsds = DataStore:GetDataStore("GrandOpeningKits")

game.Players.PlayerAdded:connect(function(player)
	local stats = Instance.new("Folder",player)
	stats.Name = "stats" -- creates a leaderboard
	
	local statsloaded = Instance.new("BoolValue")
	statsloaded.Parent = player.stats
	statsloaded.Name = "StatsLoaded"

	-- CREATES GRAND-OPENING-KITS VALUE --
	local grandopeningkits = Instance.new("NumberValue")
	
	grandopeningkits.Parent = player.stats
	grandopeningkits.Name = "GrandOpeningKits" -- creates a leaderstat value
	grandopeningkits.Value = grandopeningkitsds:GetAsync(player.UserId) or 0 -- gets past value
	grandopeningkitsds:SetAsync(player.UserId,grandopeningkits.Value) -- sets a new value
	local grandopeningkitnum = grandopeningkits.Value
	
	-- SETS STATSLOADED VALUE TO TRUE --
	statsloaded.Value = true
	
	-- LEAVE BACKUP SAVE --
	game.Players.PlayerRemoving:connect(function(player)
		print("Saving Data for user "..player.UserId)
		grandopeningkitsds:SetAsync(player.UserId,player.stats.GrandOpeningKits.Value)
		print(player.UserId.."'s Data has been saved successfully.")
		if error then
			print("DATA ERROR: "..player.UserId.."'s Data has been saved unsuccessfully")
		end
	end)
end)

I use a similar script on another game and it works fine. Anybody know whats going on?

Hello. I'm not sure if this will solve your problem, but here's the code I have created. (cloned and edited)

local DataStore = game:GetService("DataStoreService")
local grandopeningkitsds = DataStore:GetDataStore("GrandOpeningKits")

game.Players.PlayerAdded:connect(function(player)
    local stats = Instance.new("Folder",player)
    stats.Name = "stats" -- creates a leaderboard

    local statsloaded = Instance.new("BoolValue")
    statsloaded.Parent = player.stats
    statsloaded.Name = "StatsLoaded"
	statsloaded.Value = false
    -- CREATES GRAND-OPENING-KITS VALUE --
    local grandopeningkits = Instance.new("NumberValue")
	repeat wait() print('Waiting for stats folder..') until player.stats
    grandopeningkits.Parent = player.stats
    grandopeningkits.Name = "GrandOpeningKits" -- creates a leaderstat value
	local amt = grandopeningkitsds:GetAsync(player.UserId) 
	if amt == nil then amt = 0 end
    grandopeningkits.Value = amt
    
    -- SETS STATSLOADED VALUE TO TRUE --
    statsloaded.Value = true

    -- LEAVE BACKUP SAVE -- Bad idea. It will cause Datastore limit errors to break the script.
end)

    game.Players.PlayerRemoving:connect(function(player)
        print("Saving Data for user "..player.UserId)
	if player.stats.StatsLoaded.Value == true then
	local success, err = ypcall(function()
        grandopeningkitsds:SetAsync(player.UserId,player.stats.GrandOpeningKits.Value)
	end)
	if success == true then
        print(player.UserId.."'s Data has been saved successfully.")
	else print(player.UserId.."'s Data has been saved unsuccessfully.")
	end
	else
	print(player.UserId.."'s Data has been saved unsuccessfully. Had not loaded.")
	end
    end)