Script creates folders, but folders don't exist?

--I'm new at scripting--

Anyway, this is part of my script that creates the folders

local Pets = Instance.new("Folder")
local Data = Instance.new("Folder")
local Index = Instance.new("Folder")
local Quest = Instance.new("Folder")

Pets.Name = "Pets"
Data.Name = "Data"
Index.Name = "IndexFolder"
Quest.Name = "Quests"

Pets.Parent = plr
Data.Parent = plr
Index.Parent = plr
Quest.Parent = plr

They did exist just yesterday, upon changing something which I forgot what it was, the folders just don't show up anymore, and yes, I've tried doing somethings like creating a new script, which would create them aswell, but that also didn't help. Other folders, like leaderstats, do exist, but not them.