Ошибка Undefined index:

if (IsTechnologieAccessible($this->user->data, $WorkingPlanet, $elementId) && IsElementBuyable($this->user, $WorkingPlanet, $elementId) && $WorkingPlanet['b_tech_id'] == 0 && !(isset($pricelist[$elementId]['max']) && $this->user->data[$resource[$elementId]] >= $pricelist[$elementId]['max']))
        {
            $costs = GetBuildingPrice($this->user, $WorkingPlanet, $elementId);
 
            $WorkingPlanet['metal']     -= $costs['metal'];
            $WorkingPlanet['crystal']   -= $costs['crystal'];
            $WorkingPlanet['deuterium'] -= $costs['deuterium'];
 
            $time = GetBuildingTime($this->user, $WorkingPlanet, $elementId);
 
            $this->queue[self::QUEUE_TYPE_RESEARCH] = array();
 
            $this->queue[self::QUEUE_TYPE_RESEARCH][] = array
            (
                'i' => $elementId,
                'l' => ($this->user->data[$resource[$elementId]] + 1),
                't' => $time,
                's' => time(),
                'e' => time() + $time,
                'd' => 0
            );
            
            $WorkingPlanet['queue'] = json_encode($this->queue);
 
            $this->user->data["b_tech_planet"] = $WorkingPlanet["id"];
            $this->saveTechToQueue($WorkingPlanet);
        }