SQL error

ERROR:

1690 - BIGINT UNSIGNED value is out of range in '(`medziokle_press`.`c`.`isgood` - `medziokle_press`.`c`.`ispoor`)' SQL=SELECT c.userid, '' as avatar, '' as profileLink , CASE WHEN c.userid = 0 THEN c.email ELSE u.email END AS email , CASE WHEN c.userid = 0 THEN c.name ELSE u.name END AS name , CASE WHEN c.userid = 0 THEN c.username ELSE u.username END AS username , COUNT(c.userid) AS commentsCount , SUM(c.isgood) AS isgood, SUM(c.ispoor) AS ispoor, SUM(c.isgood - c.ispoor) AS votes FROM v9465_jcomments AS c LEFT JOIN v9465_users AS u ON u.id = c.userid WHERE c.published = 1 AND c.deleted = 0 GROUP BY c.userid, email, name, username, avatar, profileLink ORDER BY commentsCount DESC LIMIT 0, 25

code which is making this query:

<?php
// no direct access
defined('_JEXEC') or die;

class modJCommentsTopPostersHelper
{
    static function getList( &$params )
    {
        $db = JFactory::getDBO();
        $interval = $params->get('interval', '');

        $where = array();

        if (!empty($interval)) {
            $date = JFactory::getDate();
            $timestamp = $date->toUnix();

            switch($interval) {
                case '1-day':
                    $timestamp = strtotime('-1 day', $timestamp);
                    break;

                case '1-week':
                    $timestamp = strtotime('-1 week', $timestamp);
                    break;

                case '2-week':
                    $timestamp = strtotime('-2 week', $timestamp);
                    break;

                case '1-month':
                    $timestamp = strtotime('-1 month', $timestamp);
                    break;

                case '3-month':
                    $timestamp = strtotime('-3 month', $timestamp);
                    break;

                case '6-month':
                    $timestamp = strtotime('-6 month', $timestamp);
                    break;

                case '1-year':
                    $timestamp = strtotime('-1 year', $timestamp);
                    break;
                default:
                    $timestamp = NULL;
                    break;
            }

            if ($timestamp !== NULL) {
                if (version_compare(JVERSION,'1.6.0','ge')) {
                    $dateFrom = JFactory::getDate($timestamp)->toSql();
                    $dateTo = $date->toSql();
                } else {
                    $dateFrom = JFactory::getDate($timestamp)->toMySql();
                    $dateTo = $date->toMySQL();
                }

                $where[] = 'c.date BETWEEN ' . $db->Quote($dateFrom) . ' AND ' . $db->Quote($dateTo);
            }
        }


        switch($params->get('ordering', ''))
        {
                case 'votes':
                    $orderBy = 'votes DESC';
                    break;

            case 'comments':
            default:
                    $orderBy = 'commentsCount DESC';
                break;
        }

        $where[] = 'c.published = 1';
        $where[] = 'c.deleted = 0';

        $query = "SELECT c.userid, '' as avatar, '' as profileLink"
            . " , CASE WHEN c.userid = 0 THEN c.email ELSE u.email END AS email"
            . " , CASE WHEN c.userid = 0 THEN c.name ELSE u.name END AS name"
            . " , CASE WHEN c.userid = 0 THEN c.username ELSE u.username END AS username"
            . " , COUNT(c.userid) AS commentsCount"
            . " , SUM(c.isgood) AS isgood, SUM(c.ispoor) AS ispoor, SUM(c.isgood - c.ispoor) AS votes"
            . " FROM #__jcomments AS c"
            . " LEFT JOIN #__users AS u ON u.id = c.userid"
            . (count($where) ? ' WHERE  ' . implode(' AND ', $where) : '')
            . " GROUP BY c.userid, email, name, username, avatar, profileLink"
            . " ORDER BY " . $orderBy
            ;

        $db->setQuery($query, 0, $params->get('count'));
        $list = $db->loadObjectList();

        $show_avatar = $params->get('show_avatar', 0);

        if ($show_avatar) {
            JPluginHelper::importPlugin('jcomments');

            if (version_compare(JVERSION, '3.0', 'ge')) {
                $dispatcher = JEventDispatcher::getInstance();
            } else {
                $dispatcher = JDispatcher::getInstance();
            }

            $dispatcher->trigger('onPrepareAvatars', array(&$list));
        }

        foreach($list as &$item) {
            $item->displayAuthorName = JComments::getCommentAuthorName($item);

            if ($show_avatar && empty($item->avatar)) {
                $gravatar = md5(strtolower($item->email));
                $item->avatar = '<img src="http://www.gravatar.com/avatar.php?gravatar_id='. $gravatar .'&amp;default=' . urlencode(JCommentsFactory::getLink('noavatar')) . '" alt="'.htmlspecialchars(JComments::getCommentAuthorName($item)).'" />';
            }
        }

        return $list;
    }
}