What's the problem with this?

error is FireServer is not a valid member of RemoteFunction Script 'players.player1.playergui.sidebar.buttons.donate.donatebackg', Line 38 stack end

local Plr = game.Players.LocalPlayer
local Globals = require(game.Workspace["Globals"])
local Name = script.Parent:WaitForChild("Name")
local Amount = script.Parent:WaitForChild("Amount")
local Send = script.Parent:WaitForChild("Send")
local DonateButton = script.Parent.Parent
local ButtonP = Globals.GetButton(Plr)

DonateButton.MouseButton1Click:connect(function()
    script.Parent.Visible = not script.Parent.Visible
    if not script.Parent.Visible then
        Globals.DeleteGui(Plr,"PrivateSelling")
    else
        for i,v in pairs(DonateButton.Parent:GetChildren()) do
            if v ~= DonateButton then
                v:GetChildren()[1].Visible = false
            end
        end
    end
end)

Globals.BPreference(Send,ButtonP)
Globals.BPreference(DonateButton,ButtonP)
Globals.BPreference(script.Parent,Globals.GetBackground(Plr))
Globals.ColorPreference(DonateButton,Globals.GetColor(Plr),"TextColor3")

Amount.Changed:connect(function()
    if tonumber(Amount.Text) then
        Amount.Text = math.abs(Amount.Text)
    end
end)

Send.MouseButton1Click:connect(function()
    local Donatee = Globals.FindPlayer(Name.Text)
    if Donatee and tonumber(Amount.Text) then
        local Donation = math.abs(Amount.Text)
        if Globals.GetRobux(Plr) >= Donation then
            workspace["AwardRobux"]:FireServer({Donatee,Donation,false}) 
            workspace["RemoveRobux"]:FireServer({Plr,Donation,false})
            coroutine.resume(coroutine.create(function()
                Globals.Notify(Plr,nil,"Donated "..Donation.." to "..Donatee.Name.."!",7)
            end))
            Globals.Notify(Donatee,nil,Plr.Name.." has donated "..Donation.." to you!",7)
        else
            Globals.Notify(Plr,nil,"Not enough robux!",7)
        end
    elseif not Donatee then
        Globals.Notify(Plr,nil,Name.Text.." not found!",7)
    elseif not tonumber(Amount.Text) then
        Globals.Notify(Plr,nil,"Numbers only!",7)
    end
end)