SirChat [protocol error]

--SirChat v1.1.0 -Created by Sir.Mongoose

local ex = false
local ID = os.getComputerID()
local cl = false
local line = 3

function receive()
    local senderID, message, protocol = rednet.receive("sirchat")
    term.clearLine()
    term.setCursorPos(1,line)
    print("<ID#"..senderID.."> "..(tostring(message)))
    line = line + 1
end

function send()
    term.write("<ID#"..ID.."> ")
    local mesg = read()
    if mesg == "/exit" then
        ex = true
        term.clear()
        term.setCursorPos(1,1)
    elseif mesg == "/commands" then
        print("> '/exit' terminates the program.")
        print("> '/clear' clears chat completely.")
        print("> '/connect' connects you to a different ID.")
        print("> '/info' Tells you about SirChat.")
        line = line + 5
    elseif mesg == "/clear" then
        cl = true
    elseif mesg == "/connect" then
        connect()
    elseif mesg == "/info" then
        print("> SirChat was a program made by Sir.Mongoose.")
        print("> SirChat is currently in version 1.1.")
    elseif mesg ~= "/exit" or "/commands" or "/clear" or "/connect" or "/info" then
        rednet.send((tonumber(targetID)), (tostring(mesg)), "sirchat")
        line = line + 1
    end
end

function chat()
    term.clear()
    term.setCursorPos(1,1)
    print("**Connected with ComputerID#"..(tostring(targetID)).."**")
    print("**Type '/commands' for the list of commands**")
    while ex == false do
        parallel.waitForAny(receive, send)
        if cl == true then
            term.clear()
            term.setCursorPos(1,1)
            print("**Connected with ComputerID#"..(tostring(targetID)).."**")
            print("**Type '/commands' for the list of commands**")
            line = 3
            cl = false
        end
    end
end

function numCheck(a)
  if ((tonumber(a)) == nil) == true then
    return false
  else
    return true
   end
end

function connect()
  term.clear()
  term.setCursorPos(1,1)
  print("**Enter the ComputerID you want to connect to**")
  targetID = read()

  if numCheck(targetID) == true then
    chat()
  else
    while numCheck(targetID) == false do
        term.setCursorPos(1,2)
        term.clearLine()
        targetID = read()
    end
    chat()
  end
end

function connectModem()
term.clear()
term.setCursorPos(1,1)

  if peripheral.isPresent("back") and peripheral.getType("back") == "modem" then
    rednet.open("back")
    connect()
  elseif peripheral.isPresent("front") and peripheral.getType("front") == "modem" then
    rednet.open("front")
    connect()
  elseif peripheral.isPresent("left") and peripheral.getType("left") == "modem" then
    rednet.open("left")
    connect()
  elseif peripheral.isPresent("right") and peripheral.getType("right") == "modem" then
    rednet.open("right")
    connect()
  elseif peripheral.isPresent("top") and peripheral.getType("top") == "modem" then
    rednet.open("top")
    connect()
  elseif peripheral.isPresent("bottom") and peripheral.getType("bottom") == "modem" then
    rednet.open("bottom")
    connect()
  else
    print("**No modem connected, please place one on an available side and press enter**")
    read()
    connectModem()
   end
end

connectModem()