TFS 1.X+ Error Npc - Check task

[bpm91]

npc is not really my strong point, so if I say hi> task> Rotworms>Cancel, without having any task activated, I get this error. how to fix it? Does anyone have a direction?
tfs 1.5 7.72

Lua Script Error: [Npc interface]
data/npc/scripts/Robin.lua:onCreatureSay
data/npc/scripts/Robin.lua:135: attempt to index a boolean value
stack traceback:
        [C]: in function '__index'
        data/npc/scripts/Robin.lua:135: in function 'callback'
        data/npc/lib/npcsystem/npchandler.lua:412: in function 'onCreatureSay'
        data/npc/scripts/Robin.lua:7: in function <data/npc/scripts/Robin.lua:7>

local keywordHandler = KeywordHandler:new()
local npcHandler = NpcHandler:new(keywordHandler)
NpcSystem.parseParameters(npcHandler)

function onCreatureAppear(cid)  npcHandler:onCreatureAppear(cid)  end
function onCreatureDisappear(cid)  npcHandler:onCreatureDisappear(cid)  end
function onCreatureSay(cid, type, msg)  npcHandler:onCreatureSay(cid, type, msg)  end
function onThink()  npcHandler:onThink()  end

local difficultys = {"easy", "medium", "hard", "very hard"}
local difficulty = ""
local task = ""

function creatureSayCallback(cid, type, msg)
    local player = Player(cid)

    if (msg:lower() == "yes" and npcHandler.topic[cid] == 3) then
        playerCancelTask(player, difficulty, task)
        npcHandler:say("Ok. Done.", cid)
        npcHandler:releaseFocus(cid)
    end
   
    if (difficulty == "" and task == "" and npcHandler.topic[cid] ~= 0) then
        if (msg:lower() == "reward" or msg:lower() == "cancel" or msg:lower() == "check") then          
            if (getPlayerActualTask(player)) then
                difficulty = getPlayerActualTask(player).diff
                task = getPlayerActualTask(player).task
            else
                npcHandler:say("First choose a task..", cid)
                return true
            end
        end
    end

    if (msg:lower() == "hi") then
        npcHandler:say("Hi, i can give you a task mission.", cid)
        npcHandler:addFocus(cid)
        npcHandler.topic[cid] = 1
        return true
    end  
   
    if (not npcHandler:isFocused(cid)) then return true end
    if (msg:lower() == "task" and npcHandler.topic[cid] == 1) then
        npcHandler:say("Ok, First, choice difficulty: easy, medium, hard and very hard.", cid)
        return true
    end
   
    if (table.contains(difficultys, msg:lower())) then
        difficulty = msg:lower()
        npcHandler:say("Take a look and talk me the name of task.", cid)
        player:showTextDialog(2597, populateBookTask(difficulty), false)
    end      

    if (difficulty ~= "" and KillTaskconfig.tasks[difficulty][msg:lower()]) then
        task = msg:lower()
        npcHandler:say(string.format("Okay, %s. So, what action do you want now? accept, reward, check, cancel.", task), cid)
    end

    if (msg:lower() == "accept" and task ~= "") then
        if (KillTaskconfig.tasks[difficulty][task]) then
            if (player:getStorageValue(KillTaskconfig.storages.haveTask) == 1) then
                npcHandler:say("You already have a task. Status: "..firstToUpper(getPlayerActualTask(player).task)..": "..string.format("%s.", checkStatus(player, getPlayerActualTask(player).diff, getPlayerActualTask(player).task)), cid)
                npcHandler:addFocus(cid)
                return true
            end

            if (getPlayerTaskStatus(player, difficulty, task) == "claimed") then
                npcHandler:say("You already have been done "..task.." task.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end

            npcHandler:say("Done. Return when you complete the task.", cid)
            playerAddTask(player, difficulty, task)
            npcHandler:releaseFocus(cid)
            return true
        end
    end

    if (msg:lower() == "reward") then
        if (KillTaskconfig.tasks[difficulty][task]) then
            if (getPlayerTaskStatus(player, difficulty, task) == "claimed") then
                npcHandler:say("You already have claimed "..task.." task reward.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end

            if (getPlayerTaskStatus(player, difficulty, task) == "done") then
                player:setStorageValue(KillTaskconfig.tasks[difficulty][task].masterStorage, -3)
                player:setStorageValue(KillTaskconfig.storages.haveTask, 0)
                npcHandler:say("Okay, take your reward.", cid)
                sendPlayterTaskReward(player, difficulty, task)
                npcHandler:releaseFocus(cid)
                return true
            else
                npcHandler:say("Return when you really complete the task.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end
        end
    end

    if (msg:lower() == "check") then
        if (KillTaskconfig.tasks[difficulty][task]) then
            local val = KillTaskconfig.tasks[difficulty][task]
            if (player:getStorageValue(val.masterStorage) == 0) then
                npcHandler:say("Status: Not accepted.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end          
            if (player:getStorageValue(val.masterStorage) == -2) then
                npcHandler:say("Status: Done.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end
            npcHandler:say(string.format("Status: Task: %s, %s.", task, checkStatus(player, difficulty, task)), cid)
            npcHandler:releaseFocus(cid)
            return true
        end
    end

    if (msg:lower() == "cancel") then
        if (KillTaskconfig.tasks[difficulty][task]) then
            local val = KillTaskconfig.tasks[difficulty][task]
            if (getPlayerTaskStatus(player, difficulty, task) == "claimed") then
                npcHandler:say("You cant cancel an completed task.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end
            if (player:getStorageValue(val.masterStorage) == 0) then
                npcHandler:say("You cant cancel a non-accepted task.", cid)
                npcHandler:releaseFocus(cid)
                return true
            end
            npcHandler:say(string.format("Are you sure to cancel task %s?", getPlayerActualTask(player).task), cid)
            npcHandler.topic[cid] = 3
            return true
        end
    end
end

npcHandler:setCallback(CALLBACK_MESSAGE_DEFAULT, creatureSayCallback)