FIX this `doPlayerAddItem' (a nil value)

[legadoss]

can someone fix this?
engine: otserv

focuses = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
target = 0
following = false
attacking = false
focus2 = 0
move = true

local function isFocused(cid)
    for i, v in pairs(focuses) do
        if(v == cid) then
            return true
        end
    end
    return false
end

local function addFocus(cid)
    if(not isFocused(cid)) then
        for i, v in pairs(focuses) do
            if(v == 0)then
                focuses[i] = cid
                break
            end
        end  
    end
end

local function removeFocus(cid)
    for i, v in pairs(focuses) do
        if(v == cid) then
            focuses[i] = 0
            break
        end
    end
end

local function isFandD(cid, dist)
        if(isFocused(cid) and getDistanceToCreature(cid) < dist)then
            return true
        end
    return false
end
   
function onThingMove(creature, thing, oldpos, oldstackpos)
end

function onCreatureAppear(creature)
end

function onCreatureDisappear(cid, pos)
    if(isFocused(cid)) then
        selfSay('Good bye then.', cid)
        removeFocus(cid)
    end
end

function onCreatureTurn(creature)
end

function msgcontains(txt, str)
      return (string.find(txt, str) and not string.find(txt, '(%w+)' .. str) and not string.find(txt, str .. '(%w+)'))
end

function onCreatureSay(cid, type, msg)
      msg = string.lower(msg)
   
      if msgcontains(msg, 'hi') and (not isFocused(cid)) and getDistanceToCreature(cid) < 4 then
        selfSay('Hello ' .. creatureGetName(cid) .. '! I Exchange ', cid)
        --addFocus(cid)

    elseif msgcontains(msg, 'das') then
        doPlayerAddItem(cid,2640,1)
    elseif isFandD(cid, 4) and  string.find(msg, '(%a*)bye(%a*)')then
        selfSay('Good bye, ' .. creatureGetName(cid) .. '!', cid)
        removeFocus(cid)
        move = true
    end
end

function onCreatureChangeOutfit(creature)
end

function onThink()
    randmove = math.random(1,20)

    for i, focus in pairs(focuses) do
        if(focus > 0)then
            focus2 = focus
            move = false
        end

        if(focus ~= 0)then
            if getDistanceToCreature(focus) > 5 then
                selfSay('Good bye then.', focus)
                removeFocus(focus)
                move = true
            end
        end
    end

    if(focus2 == 0 or move)then
        cx, cy, cz = selfGetPosition()
            if randmove == 1 then
                nx = cx + 1
            end
            if randmove == 2 then
                nx = cx - 1
            end
            if randmove == 3 then
                ny = cy + 1
            end
            if randmove == 4 then
                ny = cy - 1
            end
            if randmove >= 5 then
                nx = cx
                ny = cy
            end
        moveToPosition(nx, ny, cz)
    end
end