Game crashing when a net message is called.

I am trying to create a grenade call out and when I send the message to the sever to make the player emit the sound the game crashes. I am using ents.FindInBox to locate the hl2 grenade.

Client Side


function FindTheNade()
local ply = LocalPlayer()
local Pos = ply:GetPos()
local Ents = ents.FindInBox( Pos + Vector( -16, -16, 0 ), Pos + Vector( 30, 30, 64 ) )
	if !ply.CallDelay then
		ply.CallDelay = CurTime()
	end
	for k, v in pairs( Ents ) do
		if v:GetClass() == "npc_grenade_frag" then
			if ply.CallDelay and ply.CallDelay <= CurTime() then
				ply.CallDelay = CurTime() + 10
				local sound = "Voice/bf3/vo_us_mp_alert_grenade 7 0 0.wav"
				NadeSendCall(sound)
			end
		end
	end
end
hook.Add("Think","FindTheNade", FindTheNade)

function NadeSendCall(sound)
net.Start("SendTheCall")
net.WriteString(sound)
net.SendToServer()
end

The Net Message is in a separate function because I originally was calling it in the think function and I thought that was the problem.

Server Side


util.AddNetworkString("SendTheCall")
net.Receive("SendTheCall", function(len, pl) 
local sound = net.ReadString()
pl:EmitSound(Sound(sound))
end)


This is the first time I have used ents.FindInBox so I am not sure if I am using the right hook for this.