16:17:25.947 - Workspace.Main:58: bad argument #2 to '?' (string expected, got nil)?

Imm hi I make minigame but this is code working first time but after I change the minigame time code gives this error 16:17:25.947 - Workspace.Main:58: bad argument #2 to '?' (string expected, got nil)

local s =script.Stat
local vals =game.ReplicatedStorage.Vals
t = 0
while true do
	t=15
	repeat
		t=t-1
		s.Value="Processing .."..t
		wait (1)
		
		
	until t == 0
	s.Value="ok you can start!"
	wait (0.1)
	t =50
	
	local mapselect =game.ReplicatedStorage.Maps1:GetChildren()
	local mapselectb =game.ReplicatedStorage.Maps2:GetChildren()
	local choose = math.random(1,#mapselect)
	local chooseb = math.random(1,#mapselectb)
	curnum =0
	curnumb = 0
	for i =1,#mapselect and #mapselectb do
		curnum = curnum+1
		curnumb = curnumb+1
		if curnum and curnumb == choose and chooseb then
			mapselect[i]:Clone().Parent = workspace
			mapselectb[i]:Clone().Parent = workspace
			curmap =mapselect [i].Name
			curmapb =mapselectb [i].Name
		end
	end
	wait(1)
	local plrs =game.Players:GetChildren()
		for i =1,#plrs do
			local num =math.random(1,12)
			plrs [i].Character.Head.CFrame =CFrame. new (workspace.Teleports["Part"..num].Position)
			plrs [i].Character.Parent =workspace.Ingame
		end
	repeat
		
		t=t-1
		s.Value=t.." second left"
		wait(1)
		
	until t==0 or vals.Winner.Value ~= ""
	if vals.Winner.Value ~= "" then
		s.Value =vals.Winner.Value.." has finished :F"
		game.Players[vals.Winner.Value].leaderstats.Wol.Value =game.Players[vals.Winner.Value].leaderstats.Wol.Value+10
		game.Players[vals.Winner.Value].leaderstats.Wins.Value =game.Players[vals.Winner.Value].leaderstats.Wins.Value+1
		wait(2)
		vals.Winner.Value = ""
	else
		s.Value =vals.Winner.Value.."no one finished"
		wait(2)
	end
	
	workspace[curmap and curmapb]:Destroy()

	local ingame =workspace.Ingame:GetChildren()
	for i =1,#ingame do
		local plr =game.Players:GetPlayerFromCharacter(ingame[i])
		plr:LoadCharacter()

	end
end