Why do I receive this Global Death Script error?

Hello,

I have a problem with my Global Death Script. I'ts the script that comes from AlvinBlox's Rounds tutorial series. I believe this error is throwing off other features of my game, most notably, the DataStore.

When a character is killed, or when they do a Player Reset, this error appears: -- Line 5 "bad argument #1 to 'pairs()' (table expected, got nil) "

How do I fix this error? My Global Death Script is below, I've marked the line that errors:

game:GetService('Players').PlayerAdded:connect(function(player)
    player.CharacterAdded:Connect(function(character)
        character:WaitForChild('Humanoid').Died:connect(function()
            local Update = {}
            for i,v in pairs(_G.gameplayers) do --ERROR LINE
                if v ~= player.Name then
                    table.insert(Update, 1,v)
                end
            end
            _G.gameplayers = Update
        end)
    end)
end)

_G.gameplayers is defined in the Main Script in ServerScriptService:

-- Round System Setup

_G.gameplayers = {}
for i, v in pairs(game.Players:GetPlayers()) do
if v then
table.insert(_G.gameplayers, v.Name)
end 
end

--Intermission
--Map Selection
-- Round
-- Repeat