Rednet Error: Expected Number

Trying to set up a control network, and everything was working out fine, until this code

function listen()
  local id, msg, dst
   print("Listening")
  while(true) do
	id, msg, dst = rednet.receive(10)
		print("Received ", msg)
	if (msg == "toggle") then
	  redstone.setOutput("right", true)
	  sleep(0.6)
	  redstone.setOutput("right", false)
	else
	  rednet.send(id, "13")
	end
  end
end

gives the error rednet:39: Expected number

when it receives the senders message:

rednet.send(a[y]["send"], "toggle")

and the code outputs

Listening
Received

The msg variable is not output, and I tried printing id before Received, which caused neither of them to print.

Please post your full code. This is not sufficient information to debug this problem well. For example, what is a[y]["send"]? I can only assume that it isn't a number since it is throwing that error. Unless of course the error doesn't occur on that line. We really need the full code.

rednet.receive(10) returns nil if no message is received within ten seconds. This means id, msg and dst all get set to nil, which leads to you trying to rednet.send "13" to a nil system ID.

You probably just want to use rednet.receive(), which won't return until a message comes in.

Bomb Bloke, on 24 January 2015 - 05:26 AM said:

rednet.receive(10) returns nil if no message is received within ten seconds. This means id, msg and dst all get set to nil, which leads to you trying to rednet.send "13" to a nil system ID.

You probably just want to use rednet.receive(), which won't return until a message comes in.

That was it, Thanks Bomb!!

Sorry, Bubba, I will post more context next time. My code is very poorly commented right now, it would have been a big mess to sort through.