Problem locating a Folder in Workspace:FindFirstChild(player.Name)

[NUTRICORP (Nutria)]

Well, basically I have a problem when trying to locate a Folder that is in the player’s character and it gives me the following error: ServerScriptService.SystemSellMaterialAndDrop:11: attempt to index nil with 'WaitForChild' I really don’t know what the solution is

local Storage = game:GetService("ReplicatedStorage")
local Players = game:GetService("Players")
local Event = Storage:FindFirstChild("DatosDeMaterialDrop"):FindFirstChild("UnequipMaterialEvent")

local SellMaterial = workspace:WaitForChild("MaterialSystem"):WaitForChild("Sell")

SellMaterial.Touched:Connect(function(player)
	local character = game.Workspace:FindFirstChild(player.Name)
	local Player = Players:FindFirstChild(player.Name)

	local FolderMaterial = character:WaitForChild("Sistemas")

	if FolderMaterial:IsA("Part").Name == 'Tronco' then
		FolderMaterial.SistemaDeTala.Taken.Value = false
		player:WaitForChild("FolderValues").Dinero.Value = player.FolderValues.Dinero.Value + 7
		FolderMaterial:IsA("Part"):Destroy()
	elseif FolderMaterial:IsA("Part").Name == 'Rama' then
		FolderMaterial.SistemaDeTala.Taken.Value = false
		player:WaitForChild("FolderValues").Dinero.Value = player.FolderValues.Dinero.Value + 3
		FolderMaterial:IsA("Part"):Destroy()
	end
end)

[Prototrode (Vernumerator)]

There seems to be a considerable amount of flaws in your script. Whenever you’re using :FindFirstChild or WaitForChild, you want to make sure that the object you’re looking for actually exists before doing anything with it.

local character = game.Workspace:FindFirstChild(player.Name) --what would happen if character can't be found?

local FolderMaterial = character:WaitForChild("Sistemas") --if character is nil, you're trying to run a function from a nil value which is impossible.

This is an example of how it’s supposed to look like:

local character = game.Workspace:FindFirstChild(player.Name)
if character then --if character exists, then run. otherwise, skip.
	local FolderMaterial = character:WaitForChild("Sistemas")
	--other stuff
end

Consider reading this thread:

FindFirstChild and WaitForChild: Addressing common bad practices and habits of each

Please do keep the following in mind before reading or linking! Some parts of this thread provide slightly inaccurate, unnecessary or outdated information. You are strongly encouraged to read the replies for further discussion about FindFirstChild and WaitForChild and their use in code, as well as some pointers on replication. I have not yet found a time to correct potential misconceptions in this thread. It does not provide authoritative advice and you should always double check information …

And also, I have no idea what you’re doing with the rest of your script. :IsA returns a boolean, not an instance:

FolderMaterial:IsA("Part"):Destroy()

[FamorBlox]

@NUTRICORP

local character = game.Workspace:FindFirstChild(player.Name)
	local Player = Players:FindFirstChild(player.Name)

As the other person said there are a few flaws in your script, but your current issue is that, when a part is touched it doesn’t return the player that touched it, it returns the basepart that touched it so to find the player you would do:

SellMaterial.Touched:Connect(function(part)
    if part.Parent:IsA("Model") and part.Parent.Humanoid then -- you can add more verifications if needed
        local character = part.Parent
        local player = Players:playerFromCharacter(character)
    end
end

and a little advice as a billingual person, you should code in one language because having multiple things in different languages can be confusing some times

[8_8io]

.Touched event returns a part, not a player instance.

[degamer4k]

Ignore what I previously said. Try defining the character by doing

 local character = player.Character