Attempt to index nil with FindFirstChild - lua

Question

Script:
local ToolFolder = game:GetService("ServerStorage"):FindFirstChild("SavedItems")
local DataStoreService = game:GetService("DataStoreService")
local SaveData = DataStoreService:GetDataStore("SaveData")
game.Players.PlayerAdded:Connect(function(player)
local ToolData = SaveData:GetAsync(player.UserId)
local BackPack = player:WaitForChild("Backpack")
local StarterGear = player:WaitForChild("StarterGear")
if ToolData ~= nil then
for i, v in pairs(ToolData) do
if ToolFolder:FindFirstChild(v) and BackPack:FindFirstChild(v) == nil and StarterGear:FindFirstChild(v) == nil then
ToolFolder[v]:Clone().Parent = BackPack
ToolFolder[v]:Clone().Parent = StarterGear
end
end
end
player.CharacterRemoving:Connect(function(Character)
Character:WaitForChild("Humanoid"):UnequipTools()
end)
end)
game.Players.PlayerRemoving:Connect(function(player)
local ToolTable = {}
for i,v in pairs(player.Backpack:GetChildren()) do
table.insert(ToolTable, v.Name)
end
if ToolTable ~= nil then
SaveData:SetAsync(player.UserId, ToolTable)
end
end)
Issue:
ServerScriptService.SaveTools:12: attempt to index nil with 'FindFirstChild'
Couldn't find a solution. Appreciate any help. :)

Answer 1

Any time you see "attempt to index nil with x" you need to look at where you are asking for "x" and realize that the object holding "x" doesn't exist. The job then becomes figuring out why that object doesn't exist.
In your case, whatever object that you are calling "FindFirstChild" on line 12 doesn't exist. Sadly, line 12 uses this three times :
if ToolFolder:FindFirstChild(v) and
BackPack:FindFirstChild(v) == nil and
StarterGear:FindFirstChild(v) == nil then
So let's look at where ToolFolder, BackPack, and StarterGear were created and see if that gives any clues.
local ToolFolder = game:GetService("ServerStorage"):FindFirstChild("SavedItems")
...
local BackPack = player:WaitForChild("Backpack")
local StarterGear = player:WaitForChild("StarterGear")
Backpack and StarterGear looks correct, they are both children of the Player, and both look to be spelled correctly.
ToolFolder is probably the culprit, you should make sure there is actually an object named SavedItems in ServerStorage. Double check that the spelling and capitalization are correct.