attempt to index nil with 'GetChildren' Line 56?

i've been trying to fix this for the past 3 days, please help

-- Vars

	local ReplicatedStorage = game:GetService("ReplicatedStorage")
	
	local ServerStorage = game:GetService("ServerStorage")
	
	local MapsFolder = ServerStorage:WaitForChild("Maps")
	
	local Status = ReplicatedStorage:WaitForChild("Status")
	
	local GameLength = 180
	
	
	-- Loop The Game If No One Wins
	
	while true do
		
		Status.Value = "2 players needed to start the game"
		
		repeat wait(1) until game.Players.NumPlayers >=2
		
		Status.Value = "Intermission"
		
		wait(20)
		
		local plrs = {}
		
		for i, player in pairs(game.Players:GetPlayers()) do
			if player then
				
				table.insert(plrs,player)-- add players to table
				
			end
		end
		wait(2)
		
		local availableMaps = MapsFolder:GetChildren()
		
		local ChosenMap = availableMaps[math.random(1,#availableMaps)]
		
		Status.Value = ChosenMap.Name.." was picked"
		
		local ClonedMap = ChosenMap:Clone()
		
		ClonedMap.Parent = workspace
		
		
		--Tp players
		
		local SpawnPoint = ClonedMap:FindFirstChild("SpawnPoints")
		
		if not SpawnPoint then
			print("Spawnpoints is not found")
		end
		
		local AvailableSpawnPoint = SpawnPoint:GetChildren()
		
		for i, player in pairs(plrs) do
			if player then
				character = player.Character
				
				if character then 
					-- tp
					character:FindFirstChild("Torso").CFrame = AvailableSpawnPoint[1]
					table.remove(AvailableSpawnPoint,1)
					
					--give a tool
					
					local Sword = ServerStorage.Sword.Clone()
					Sword.Parent = player.Backpack
					
					local GameTag = Instance.new("BoolValue")
					GameTag.Name = "GameTag"
					GameTag.Parent = player.Character
					
					
					
				else
					-- is no char
					
					if not player then
						table.remove(plrs,i)
					end
				end
			end
		end
		
		
		Status.Value = "Starting Game"
		
		wait(2)
		for i = GameLength,0,-1 do
			
			for x, player in pairs(plrs) do
				if player then
					character = player.Character
					if not character then
						-- left
					else
							if character:FindFirstChild("GameTag")then
								print(player.Name.."is still in the game")
							else
									-- they are deade
									table.remove(plrs,x)
									print(player.Name.."has been removed")
							end
					end
				end
				
					table.remove(plrs,x)
					print(player.Name.."has been removed")
				
			end
			
			Status.Value = i.." time left, and "..plrs.." Players left"
			
			if #plrs == 1 then
				Status.Value = plrs[1].Name.." has won the game."
				plrs[1].leaderstats.Coins.Value = plrs[1].leaderstats.Coins.Value + 200
				
				break
				
				elseif #plrs == 0 then
					Status.Value = "Sadly, no one won"
					break
					
					elseif i == 0 then
						Status.Value = "Time's up lads'. Good luck next time"
					break
				end
			
			wait(1)
		end
		
		print("End of game")
		
		for i, player in pairs (game.Players:GetPlayers()) do
			character =  player.Character
			
			if not character then
				--ignore
			else 
				if character:FindFirstChild("GameTag") then
					character.GameTag:Destroy()
				end
				if player.Backpack:FindFirstChild("Sword") then
					player.Backpack.Sword:Destroy()
				end
				if character.Backpack:FindFirstChild("Sword") then
					character.Sword:Destroy()
			end
		end
			
			
		player:LoadCharacter()
	end
			
		
		
		
	ClonedMap:Destroy()
		
	Status.Value = "Game ended"
		
	wait(2)
end
		
		
		

this script is from alvinblox, but i cant seem to find out how to fix it