(Miner's Haven open source) Custom items throwing errors when I try to give myself said item?

So I am a complete noob with code, but I can at least somewhat figure out what stuff does. When I add a custom item into MH (submissions from toolbox), give it a unique ID and make sure it has all the things it should like the cost, itemtype, etc. and add a code to give me one of said item, it does nothing, just gives an error. Error I mentioned

Here's line 26-43 of the code that's throwing the error

function awardItem(Player, ItemId, Amount)  
    Amount = Amount or 1
    local Item = getItem(ItemId)
    if Item then
        if _G["Inventory"][Player.Name] ~= nil and _G["Inventory"][Player.Name][ItemId] ~= nil and _G["Inventory"][Player.Name][ItemId].Quantity ~= nil then
            _G["Inventory"][Player.Name][ItemId].Quantity = _G["Inventory"][Player.Name][ItemId].Quantity + Amount
        else
            _G["Inventory"][Player.Name][ItemId].Quantity = Amount
        end
        game.ReplicatedStorage.ItemObtained:FireClient(Player,Item,Amount)
        --game.ReplicatedStorage.Hint:FireClient(Player,"You were awarded "..Amount.." "..Item.Name..".",nil,Color3.new(0.5,0.5,0),"Obtained")
        game.ReplicatedStorage.InventoryChanged:FireClient(Player,_G["Inventory"][Player.Name],ItemId)
        return true
    else
        print("Could not find item")
    end
    return false
end

Screenshot of it, sorry I couldn't fit it all

This is the code I tweaked to give me the custom item I added

{"testitem",Award,100076,1},

testitem is the code I need to put in the "secret code" box, Award is what tells the game it's an item, 100076 is the ID I gave the custom item (facemashed the ID when I made it), and 1 is the quantity. the original is the following

{"hyup",Award,400,1},

No matter what I do that I'm capable of doing, it never works. I compare it to the basic game's items and I see no difference. I can use some tweaked code to give myself anything else already in the game, but nothing that I add it seems.

Item already in the game

Item I'm trying to add

If anyone has any ideas please let me know. If there isn't enough information I'll add anything else that may be relevant. This is my first post on any website, so my apologies if it looks like a mess, or if I take a while to reply.