Trying to save placement of furniture over DataStore and I am getting Error 104; what is the issue?

game.Close:Connect(function()
    local saveFolder = workspace.placedFurniture
    local saves = saveFolder:GetChildren()
    local saveFurnitureTable = {}
    for i = 1, #saves do
        local save = {}
        save["folderName"] = saves[i].Name
        local furniture = saves[i]:GetChildren()
        for i = 1, #furniture do
            save[furniture[i].Name] = furniture[i].PrimaryPart.CFrame
        end
        saveFurnitureTable[i] = save
    end
    local Success, Error = pcall(function()
      return game:GetService("DataStoreService"):GetDataStore("SAVE"):SetAsync("Furniture", saveFurnitureTable)
    end)
    if Error then
        warn(Error)
    end
end)

Output as requested. 104: Cannot store Array in data store. Data stores can only accept valid UTF-8 characters.