gui problems in Filtering enabled?

I've got a "cash exchange system" you type in the amount of cash that you want to give to someone, then press a button. It puts a bag in your inventory with the amount of money that you put in the text box. The only problem is that I cant get the amount of money that is suppose to be put in the bag with filtering enabled on. I get the error : attempt to index a nil value. When I try to get the amount in a server script. Here is the code:

Local script (in gui):

local Player = game.Players.LocalPlayer

script.Parent.MouseButton1Click:Connect(function()
    local text = script.Parent.Parent.AmountBox
    local Amount = tonumber(text.Text)

    if Player.Stats.Beli.Value >= Amount and Amount ~= 0 and Amount > -1 then
    script.Parent.Parent.Parent.Parent.UI_Click:Play()
    Player.Backpack.BeliClicked:FireServer()


    elseif  Player.Stats.Beli.Value < Amount or Amount ~= 0 or Amount > -1 then
        script.Parent.Parent.Parent.Parent.UI_Error:Play()
    end
end)

Server sided script(in backpack):

script.Parent.BeliClicked.OnServerEvent:Connect(function(Player)
        local text = Player.PlayerGui:FindFirstChild("Main"):FindFirstChild("DropBeli"):FindFirstChild("AmountBox") --error comes from here
        local Amount = tonumber(text.Text)
        script.value.Value = Amount 

        if Player.Stats.Beli.Value >= script.value.Value then
            Player.Stats.Beli.Value = Player.Stats.Beli.Value - script.value.Value
            local bag = game.ReplicatedStorage.Items.MoneyBag:Clone()
            bag.Handle.Amount.Value = script.value.Value
            bag.Parent = Player.Backpack
            bag.ToolTip = (script.value.Value)
    end
end)