Need help with Addon Script.

[axxon]

On the beggining, everything worked perfectly fine, but now i got this message in the server console:
Lua Script Error: [NPC Interface]
data/npc/scripts/addon.luanCreaturesay
data/npc/scripts/addon.lua:61: attempt to call ´global´<a number value>

I use this script
local focus = 0
local talk_start = 0
local target = 0
local following = false
local attacking = false

function onThingMove(creature, thing, oldpos, oldstackpos)

end


function onCreatureAppear(creature)

end


function onCreatureDisappear(cid, pos)
if focus == cid then
selfSay('Good bye then.')
focus = 0
talk_start = 0
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 (focus == 0)) and getDistanceToCreature(cid) < 4 then
selfSay('Hello ' .. creatureGetName(cid) .. '! I sell the first addon for 75k and the second addon for 75k.')
focus = cid
talk_start = os.clock()

elseif msgcontains(msg, 'hi') and (focus ~= cid) and getDistanceToCreature(cid) < 4 then
selfSay('Sorry, ' .. creatureGetName(cid) .. '! I talk to you in a minute.')

elseif focus == cid then
talk_start = os.clock()

if msgcontains(msg, 'first addon') then
selfSay('Do you want to buy the first addon for 5k?')
talk_state = 1

elseif msgcontains(msg, 'second addon') then
selfSay('Do you want to buy the second addon for 10k?')
talk_state = 2

elseif talk_state == 1 then
if msgcontains(msg, 'yes') then
if pay(cid,10000) then
addon(cid, 1)
else
selfSay('Sorry, you don\'t have enough money.')
end
end
talk_state = 0

elseif talk_state == 2 then
if msgcontains(msg, 'yes') then
if pay(cid,5000) then
addon(cid, 2)
else
selfSay('Sorry, you don\'t have enough money.')
end
end
talk_state = 0

elseif msgcontains(msg, 'bye') and getDistanceToCreature(cid) < 4 then
selfSay('Good bye, ' .. creatureGetName(cid) .. '!')
focus = 0
talk_start = 0
end
end
end


function onCreatureChangeOutfit(creature)

end


function onThink()
doNpcSetCreatureFocus(focus)
if (os.clock() - talk_start) > 30 then
if focus > 0 then
selfSay('Next Please...')
end
focus = 0
end
if focus ~= 0 then
if getDistanceToCreature(focus) > 5 then
selfSay('Good bye then.')
focus = 0
end
end
end

and in data/npc/Mahadris
<npc name="Mahadris" script="data/npc/scripts/addon.lua" lookdir="3" autowalk="25">
<health now="500" max="500"/>
<look type="104" head="20" body="100" legs="50" feet="99"/>
</npc>

The wierd thing is that it worked before and i didnt change anything