why won t this script work on roblox player?

script.Parent.MouseButton1Click:connect(function()
-- Inside Server Script
local event = Instance.new("RemoteEvent") -- creates the event object
event.Parent = game.Workspace -- puts the event into the Workspace
event.Name = "MyServerEvent" -- giving a name to the event so we can fire it specifically elsewhere
event.OnServerEvent:connect(function() -- define the function that will be called when the event is fired
	local player = script.Parent.Parent.Parent.Parent
	local char = player.Character
	local human = char:FindFirstChild("Humanoid")
	local model = script.Parent.Parent.Model.Value
	local car = script.Parent.Parent.Car.Value
	if human:FindFirstChild(model)~= nil then
		print("Model Found!")
		if human:FindFirstChild(model):FindFirstChild(car) ~= nil then
			print("Car Found!")
			local body = human:FindFirstChild(model):FindFirstChild(car):GetChildren()
			for i,v in pairs (body) do
				if v.Name == "Seat" then
					v.Disabled = true
					script.Parent.Parent.Open.Visible = true
					script.Parent.Visible = false
				end
			end
		end
	end
end)
	game.Workspace.MyServerEvent:FireServer()
end)

this script works on studio but not on the roblox player. the error below pops up. why? please help 23:29:39.113 - OnServerEvent can only be used on the server 23:29:39.114 - Script 'Players.Player2.PlayerGui.VehicleGui.Lock.LocalScript', Line 6 23:29:39.114 - Stack End

You can't handle the server side part of a RemoteEvent; you have to place to OnServerEvent Code in a Server Script.