Lua Attempt to index global 't' (a nil value)

[Dankasby]

I added a system of the inquisition teleports. But when I kill other monsters (except bosses of the Inquisition), he does not die and this error appears




The script:

local config = {
        timeToRemove = 180, -- segundos
                message = "Go into the teleport in 180 seconds, else it will disappear.",
        teleportId = 9773,
        bosses = { -- Nome do monstro,  Posicao do teleporte
                ["Ushuriel"] = {  pos={x=1294, y=705, z=15, stackpos=1}, aid=11001 },
                ["Zugurosh"] = {  pos={x=1328, y=704, z=15, stackpos=1}, aid=11002},
                ["Madareth"] = {  pos={x=1291, y=731, z=15, stackpos=1}, aid=11003},
                ["Annihilon"] = {  pos={x=1366, y=689, z=15, stackpos=1}, aid=11005},
                ["Hellgorak"] = {  pos={x=1371, y=731, z=15	, stackpos=1}, aid=11006},
				["Latrivan"] = {pos={x=1326, y=735, z=15, stackpos=1},aid=11004}

}	}	
 local function change(position)
        doItemSetAttribute(getTileItemById(position, config.teleportId).uid, "aid", 3000)
    return TRUE
end

function onKill(cid, target, lastHit)
    if(config.bosses[getCreatureName(target)]) then
                local t = config.bosses[getCreatureName(target)]
                local position = t.pos
                doItemSetAttribute(getTileItemById(position, config.teleportId).uid, "aid", t.aid)
				doCreatureSay(cid, config.message, TALKTYPE_ORANGE_1)
                addEvent(change, config.timeToRemove * 1000, position)
				return TRUE
		
		else
                        local position = t.pos
                        doItemSetAttribute(getTileItemById(position, config.teleportId).uid, "aid", t.aid)
                        doItemSetAttribute(teleport, "aid", t.aid)
                        doCreatureSay(cid, config.message, TALKTYPE_ORANGE_1)
                        addEvent(removal, config.timeToRemove * 1000, position)
                end
        end
        return TRUE

Anyone help me ?
Thanks.