attempt to call method 'DoClick' (a nil value)

[COMBOBREAKER]

Hello. So I am new to coding Lua and i was working on an entity with derma where if you use the entity you would get a derma popup asking if you would like to purchase with yes and no buttons. Anyway so i have set it up but i get a script error when i click yes on my derma panel.

[ERROR] lua/vgui/dlabel.lua:218: attempt to call method 'DoClick' (a nil value)
  1. unknown - lua/vgui/dlabel.lua:218

And here are my clientside and server lua files

init.lua

AddCSLuaFile("cl_init.lua")
AddCSLuaFile("shared.lua")
include("shared.lua")

function ENT:Initialize()

self:SetModel("models/Items/ammocrate_grenade.mdl")
self:PhysicsInit(SOLID_VPHYSICS)
self:SetMoveType(MOVETYPE_VPHYSICS)
self:SetSolid(SOLID_VPHYSICS)
local phys = self:GetPhysicsObject()
if phys:IsValid() then
	phys:Wake()

	end
end


function ENT:Use(activator,caller)
	self:SetUseType(SIMPLE_USE)
	umsg.Start("DrawShopMenu", activator)
	umsg.Short("1")
	umsg.End()
	

end

util.AddNetworkString("buttonpress1")
net.Receive("buttonpress1", buttonpress1)

function buttonpress1()
print ("hello!")
end

cl_init.lua

include("shared.lua")

function ENT:Draw()


self:DrawModel()

end

function DrawShopMenu()
local frame = vgui.Create("DFrame")
    frame:SetSize(400, 100)
    frame:Center()
    frame:SetTitle('Armor Shop')
    frame:ShowCloseButton(true)
    frame:SetSizable(false)
    frame:SetDeleteOnClose(true)
    frame:MakePopup()
	
	local button = vgui.Create("DButton",frame)
	button:SetPos (10,55)
	button:SetSize(100,40)
	button:SetText("Yes")
	button.DoClick = buttonpress1()
	
	net.Start("buttonpress1")
	net.SendToServer()
	
	local button2 = vgui.Create("DButton",frame)
	button2:SetPos (290,55)
	button2:SetSize(100,40)
	button2:SetText("No")
	
	local label = vgui.Create("DLabel",frame)
	label:SetPos(120,30)
	label:SetText("Would you like to purchase armor?")
	label:SetSize(165,16)
	
end
usermessage.Hook("DrawShopMenu",DrawShopMenu)

[Its Pawsative]

You're trying to call a serverside function on the client.

Do this instead:

[lua]
button.DoClick = function()

net.Start("buttonpress1")
net.SendToServer()

end
[/lua]

[COMBOBREAKER]

thankyou a buttload, i was watching a video on derma and looking at posts and it thought that where function() was i was suppose to put a certain function in its place. Just a stupid mistake that i spent way too long trying to fix. Thanks again