attempt to index number with 'Stage'? (line 25)

local DataStoreService = game:GetService("DataStoreService")
local CheckpointDataStore = DataStoreService:GetDataStore("CheckpointDS")

game.Players.PlayerAdded:Connect(function(player)
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player
	
	local Stage = Instance.new("IntValue")
	Stage.Name = "Stage"
	Stage.Parent = leaderstats
	
	local Won = Instance.new("BoolValue")
	Won.Name = "Won"
	Won.Parent = player
	
	local playerUserId = "Key_"..player.UserId
	
	local data
	local success, errorMessage = pcall(function()
		data = CheckpointDataStore:GetAsync(playerUserId, data)
	end)
	
	if success then
		Stage.Value = data.Stage
		Won.Value = data.Won
		print("Successfully Loaded Player Data!")
	end
	
	game.ReplicatedStorage.SaveData.OnServerEvent:Connect(function(player)
		print("Saved "..player.Name.."'s Data!")
		
		local success, errorMessage = pcall(function()
			CheckpointDataStore:SetAsync(playerUserId, data)
		end)
		
		if success then
			print("Successfully Saved "..player.Name.."'s Data!")
		else
			warn(errorMessage)
		end
	end)
	
	while true do wait(30)
		local WaitTime = math.random(2,5)
		for i,v in pairs(game.Players:GetPlayers()) do
			if v.PlayerGui.SaveData.SaveMsg.Visible == false then
				v.PlayerGui.SaveData.SaveMsg.Visible = true
				v.PlayerGui.SaveData.SaveMsg.Text = "Saving Data..."
				v.PlayerGui.SaveData.SaveMsg.TextColor3 = Color3.fromRGB(255,255,0)
			end
		end
		print("Saving Data...")
		wait(WaitTime)
		print("Successfully Auto Saved Data!")
		CheckpointDataStore:SetAsync(playerUserId, player.leaderstats.Stage.Value)
		for i,allplayers in pairs(game.Players:GetPlayers()) do
			allplayers.PlayerGui.SaveData.SaveMsg.Text = "Successfully Saved Data!"
			allplayers.PlayerGui.SaveData.SaveMsg.TextColor3 = Color3.fromRGB(85,255,0)
		end
		wait(2)
		for i,allplayers in pairs(game.Players:GetPlayers()) do
			allplayers.PlayerGui.SaveData.SaveMsg.Text = ""
			allplayers.PlayerGui.SaveData.SaveMsg.TextColor3 = Color3.fromRGB(115,115,115)
			allplayers.PlayerGui.SaveData.SaveMsg.Visible = false
		end
	end
	
end)

game.Players.PlayerRemoving:Connect(function(player)
	local playerUserId = "Key_"..player.UserId
	
	local data = {
		Stage = player.leaderstats.Stage.Value;
		Won = player.Won.Value;
	}
	
	local success, errorMessage = pcall(function()
		CheckpointDataStore:SetAsync(playerUserId, data)
	end)
	
	if success then
		print("Player Data Successfully Saved!")
	else
		print("There was an error whilst saving data!")
		warn(errorMessage)
	end
end)