I got this error that breaks the whole game, how could I fix the problem?
It’s hard to try to fix the problem because it works like 99% of the time, so I would appreciate all kind of help.
This is where it breaks, if you want more code just ask 
if v:IsInGroup(9340560) == true then
v.leaderstats[bitname].Value = v.leaderstats[bitname].Value + 5
end
Thank you,
/Xsodar
Could you show your i,v loop? 
Here it is, the whole function.
function module.Winners(reward,bitname,winname)
runningFunction.Value = "Winners"
local playersnowin = 0
for i,v in pairs(game.Players:GetChildren()) do
if workspace:FindFirstChild("Minigame") and v:FindFirstChild("RankSystem") and v.RankSystem:FindFirstChild("Current") and v:FindFirstChild("leaderstats") and v.leaderstats:FindFirstChild(bitname) and v.leaderstats:FindFirstChild(winname) and v:FindFirstChild("Playing") and v.Playing.Value == true then
local vip = v.Passes:FindFirstChild("PlayerHasVIP")
local passExp = v.Passes:FindFirstChild("PlayerHasXTwoExp")
local passBits = v.Passes:FindFirstChild("PlayerHasXTwoBits")
if gamefolder.Players.Value <= workspace.Minigame.GameConfig.PlayersToEnd.Value then
status.Value = ""
if v:IsInGroup(9340560) == true then
v.leaderstats[bitname].Value = v.leaderstats[bitname].Value + 5
end
if passExp.Value == true and vip.Value == false then
v.RankSystem.Current.Value = v.RankSystem.Current.Value + 20
end
if passBits.Value == true and vip.Value == false then
v.leaderstats[bitname].Value = v.leaderstats[bitname].Value + 20
end
if vip.Value == true then
if vip.Value == true and passBits.Value == true then
v.leaderstats[bitname].Value = v.leaderstats[bitname].Value + 60 -- Pass BIT
elseif vip.Value == true and passBits.Value == false then
v.leaderstats[bitname].Value = v.leaderstats[bitname].Value + 20
end
if vip.Value == true and passExp.Value == true then
v.RankSystem.Current.Value = v.RankSystem.Current.Value + 40 -- Pass EXP
elseif vip.Value == true and passExp.Value == false then
v.RankSystem.Current.Value = v.RankSystem.Current.Value + 10
end
end
v.leaderstats[bitname].Value = v.leaderstats[bitname].Value + reward
v.leaderstats[winname].Value = v.leaderstats[winname].Value + 1 --Normal reward
v.RankSystem.Current.Value = v.RankSystem.Current.Value + 20
game.ReplicatedStorage.Remotes.PlayerWins:FireAllClients(v)
else
status.Value = "No Winner!"
end
else
playersnowin = playersnowin + 1
end
if playersnowin == i then
status.Value = "No Winner!"
end
end
end
May I suggest instead of GetChildren() you instead use GetPlayers()?
Okay I can try that, will this solve this error or is something else you can do to make it even better?
Is gamefolder ever defined? {30ChARRAS}
Try using
for i,v in pairs (game.Players:GetPlayers()) do
GetChildren() returns every object parented inside the player, not the individual Player Instances; if you want to check that a Player is in a specific group, use GetPlayers() method like @ItsNickBoi110 mentioned
Most likely means that the player has left the game lol.
The method returns an error. Meaning the method exists on the player.
Just run an integrity Check by doing the following
if not Player or Player.Parent ~= game.Players then return end
local gamefolder = game.ReplicatedStorage.Game
I have this in the beginning of the script so yes.
This will not work as you are not using any type of method once you define game.Players. 
Are you still receiving the error even after you changed it to GetPlayers()?
My bad I should have caught myself on that I haven’t scripted in a while.
It’s alright, but I would also like to mention GetPlayers() only returns Player instances, so technically there would be no use in using if v:IsA('Player') then.
Yea, true i’m also rlly tired rn just got back from a baseball game. 
This error does not happen all the time so I don’t know, but I did what @AsynchronousMatrix and also did what you suggested. So I think it will work, thanks.
This seems to be a reoccurring issue while using the method IsInGroup(), perhaps file a bug report!