Problem with variables in OpenComputers

local component = require("component");
local event = require("event");
local computer = require("computer");
local redstone = component.redstone;
local gpu = component.gpu;
local modem = component.modem;
local InPort = 114;
local OutPort = 1984;
local CommPort = 3666;

local Captain = "Aex";
local userlist = {};
local TrustedAddr = "";

modem.open(InPort);

local resX = 30
local resY = 10
gpu.setResolution(resX, resY);

local sMode = 1;    -- -1 - Wait Menu, 0 - Admin, 1 - Main Menu,
local cTask = 0;    -- 0 - Nothing, 1 - Door open, 2 - Message pending
local TimeOut = 0;
local sCL = 0;
local GuestName = "";
local timestamp = computer.uptime();

local DefMsg = "    WELCOME TO METROPOLIS"
local RSside = 3;
local Defcon = 4; -- 5 - open doors, _4_ - Only friends, 3 - Only owner, 2 - Ignore, radar sweeps, 1 - Exterminate
local MailBlock = -1;       -- 0 - allowed, 1 - blocked

modem.setStrength(0);

function getUptime(tTime)
  local tTime = computer.uptime();
  local tDays = math.floor(tTime/86400);
  local tHours = math.floor((tTime%86400)/3600);
  local tMinutes = math.floor((tTime%3600)/60);
  local tSeconds = math.floor(tTime%60);
  return tDays.."d, "..tHours..":"..tMinutes..":"..tSeconds;
end

function ClrScr()
    gpu.setBackground(0x000000);
    gpu.fill(1,1, resX, resY, " ");
end

function ClrMsg()
    gpu.setBackground(0x000000);
    gpu.setForeground(0xFFFFFF);
    gpu.fill(2, 2, 28, 3, " ");
end

function DisplayMsg(msg, line)
    gpu.setBackground(0x000000);
    gpu.setForeground(0xFFFFFF);
    gpu.fill(2, line+1, 28, 1, " ");
    gpu.set(2, line+1, tostring(msg));
end

function DisplayDefMsg()
    ClrMsg();
    DisplayMsg(DefMsg, 2, 0);
end

function OpenDoor()
    redstone.setOutput(3, 16);
    cTask = 1;
    WaitMenu(3);
end

function ShowMenu()
    ClrScr();
    -- Draw message pane
    gpu.setForeground(0xFFFFFF);
    gpu.fill(1,1,resX, 1, "=");
    gpu.fill(1,2,1,3,"|");
    gpu.fill(resX,2,1,3,"|");
    gpu.fill(1,5,resX,1,"=");

    gpu.set(10, 1, "METROPOLIS");

    --gpu.set(3, 3, "WELCOME TO METROPOLIS");

    -- Draw buttons
    gpu.setBackground(0xFFFFFF);
    gpu.setForeground(0x000000);
    gpu.fill(2,7,12,3, " ");
    gpu.fill(16,7,12,3, " ");

    -- Button captions
    gpu.set(7, 8, "VISIT");
    gpu.set(18, 8, "MSG");

    gpu.setForeground(0xFFFFFF);
    gpu.setBackground(0x000000);

    DisplayDefMsg();

    TimeOut = 0;
    sMode = 1;
    cTask = 0;
end

function AdminMenu()

end

function WaitMenu(delay)
    sMode = -1;
    TimeOut = delay;
    timestamp = computer.uptime();
    gpu.fill(1,7, resX, resY, " ");
    gpu.set(8, 9, "PLEASE WAIT");
end

function InitHost()

end

function InitRobot()

end

function VisitRequest()
    sGuestName = GuestName;
    if (GuestName == Captain) then
        DisplayMsg("Welcome back, "..Captain.."!", 1);
        OpenDoor();
        WaitMenu(3);
    end;
end


function MsgRequest()

end

ShowMenu();
while true do
    local msg = {event.pull(1)};
    if (msg[1] == "touch") then
        GuestName = msg[6];
        if (msg[4] < 3) and (msg[6] == Captain) then
            AdminMenu();
        else
            if (sMode == 1) and (msg[4] > 6) then
                -- Main Menu
                if (msg[3] < 15) then
                    -- VISIT
                    VisitRequest(msg[6]);
                else
                    MsgRequest(msg[6]);
                end
            end
        end
    end -- IF Event

    if (computer.uptime() - timestamp > TimeOut) and (TimeOut > 0) then
        if (cTask == 1) then
            redstone.setOutput(3, 0);
        elseif (cTask == 2) then
            modem.close(CommPort);
            modem.setStrength(0);
        end
        ShowMenu();
    end
    if (TimeOut == 0) and (redstone.getOutput(3) > 0) then
        redstone.setOutput(3, 0);
    end

    gpu.fill(1, 10, 20, 1, " ");
    gpu.set(1, 10, tostring(getUptime()).." "..tostring(TimeOut));
    os.sleep(0);
end