This is the error. I repair the file article_dao.php and now is ok. this is the correct source code, I sure would deserve a free plugin from the developer for fixing this bug

<?php
class ARTICLES_BOL_ArticleDao extends OW_BaseDao{    const CACHE_TAG_ARTICLE_COUNT = 'articles.article_count';    const CACHE_LIFE_TIME = 86400; //24 hour
    /**     * Class constructor     *     */    protected function __construct()    {        parent::__construct();    }    /**     * Class instance     *     * @var ARTICLES_BOL_ArticleDao     */    private static $classInstance;
    /**     * Returns class instance     *     * @return ARTICLES_BOL_ArticleDao     */    public static function getInstance()    {        if ( self::$classInstance === null )        {            self::$classInstance = new self();        }
        return self::$classInstance;    }
    /**     * @see OW_BaseDao::getDtoClassName()     *     */    public function getDtoClassName()    {        return 'ARTICLES_BOL_Article';    }
    /**     * @see OW_BaseDao::getTableName()     *     */    public function getTableName()    {        return OW_DB_PREFIX . 'articles_article';    }
    public function findAdjacentUserArticle( $id, $articleId, $which )    {        $part = array();
        switch ( $which )        {            case 'next':                $part['projection'] = 'MIN(`id`)';                $part['inequality'] = '>';                break;
            case 'prev':                $part['projection'] = 'MAX(`id`)';                $part['inequality'] = '<';                break;        }
        $query = "SELECT {$part['projection']}FROM {$this->getTableName()}WHERE isDraft = 0 AND authorId = ? AND id {$part['inequality']} ?";
        $id = $this->dbo->queryForColumn($query, array($id, $articleId));
        return (!empty($id)) ? $this->findById($id) : null;    }
    public function deleteByAuthorId( $userId )    {        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $userId);
        $this->deleteByExample($ex);    }
    public function findUserArticleList( $userId, $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $userId)            ->setOrder('`timestamp` DESC')            ->andFieldEqual('isDraft', 0)            ->setLimitClause($first, $count);
        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->findListByExample($ex, $cacheLifeTime, $tags);    }
    public function findUserDraftList( $userId, $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $userId)            ->andFieldNotEqual('isDraft', 0)            ->setOrder('`timestamp` DESC')            ->setLimitClause($first, $count);
        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->findListByExample($ex, $cacheLifeTime, $tags);    }
    public function countUserArticle( $userId )    {        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $userId);        $ex->andFieldEqual('isDraft', 0);
        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->countByExample($ex,$cacheLifeTime, $tags);    }    public function countCategoryArticle( $catId )    {        $ex = new OW_Example();        $ex->andFieldEqual('categoryId', $catId);        $ex->andFieldEqual('isDraft', 0);
        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->countByExample($ex,$cacheLifeTime, $tags);    }
    public function countUserDraft( $userId )    {        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $userId);        $ex->andFieldNotEqual('isDraft', 0);        $ex->andFieldNotEqual('isDraft', 3);
        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->countByExample($ex, $cacheLifeTime, $tags);    }
    public function countArticles($optionalParmams = array())    {        $ex = new OW_Example();        $ex->andFieldEqual('isDraft', 0);        $ex->andFieldEqual('privacy', 'everybody');    foreach ($optionalParmams as $key => $value){        $ex->andFieldEqual($key, $value);        }        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->countByExample($ex, $cacheLifeTime, $tags);    }
    public function countUserArticleComment( $userId )    {        $query = "SELECT COUNT(*)FROM `{$this->getTableName()}` as `p`INNER JOIN `" . BOL_CommentEntityDao::getInstance()->getTableName() . "` as `ce`ON( `p`.`id` = `ce`.`entityId` and `entityType` = 'article-article' )INNER JOIN `" . BOL_CommentDao::getInstance()->getTableName() . "` as `c`ON( `ce`.`id` = `c`.`commentEntityId` )
WHERE `p`.`authorId` = ? AND `p`.`isDraft` = 0";
        return $this->dbo->queryForColumn($query, array($userId));    }
    public function countUserArticleNewComment( $userId )    {        $query = "SELECT COUNT(*)FROM `{$this->getTableName()}` as `p`INNER JOIN `" . BOL_CommentEntityDao::getInstance()->getTableName() . "` as `ce`ON( `p`.`id` = `ce`.`entityId` and `entityType` = 'article-article' )INNER JOIN `" . BOL_CommentDao::getInstance()->getTableName() . "` as `c`ON( `ce`.`id` = `c`.`commentEntityId` )
WHERE `p`.`authorId` = ? AND `p`.`isDraft` = 0 AND `c`.`createStamp` > ".(time()-86400*7)."";
        return $this->dbo->queryForColumn($query, array($userId));    }
    public function findUserArticleCommentList( $userId, $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $query = "SELECT `c`.*, `ce`.`entityId`FROM `{$this->getTableName()}` as `p`INNER JOIN `" . BOL_CommentEntityDao::getInstance()->getTableName() . "` as `ce`ON( `p`.`id` = `ce`.`entityId` and `entityType` = 'article-article' )INNER JOIN `" . BOL_CommentDao::getInstance()->getTableName() . "` as `c`ON( `ce`.`id` = `c`.`commentEntityId` )
WHERE `p`.`authorId` = ? AND `p`.`isDraft` = 0ORDER BY `c`.`createStamp` DESCLIMIT ?, ?";
        return $this->dbo->queryForList($query, array($userId, $first, $count));    }
    public function findUserLastArticle( $userId )    {        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $userId)->andFieldEqual('isDraft', 0)->setOrder('timestamp DESC')->setLimitClause(0, 1);
        return $this->findObjectByExample($ex);    }
    public function findUserArchiveData( $id ){    $query = "        SELECT YEAR( FROM_UNIXTIME(`timestamp`) ) as `y`, MONTH( FROM_UNIXTIME(`timestamp`) ) as `m`        FROM `{$this->getTableName()}`        WHERE isDraft = 0 AND `authorId` = ?        GROUP BY `y`, `m`        ORDER BY `y` DESC, `m` DESC    ";
    return $this->dbo->queryForList($query, array($id));}
    public function findUserArticleListByPeriod( $id, $lb, $ub, $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $id);
        $ex->andFieldBetween('timestamp', $lb, $ub);        $ex->andFieldEqual('isDraft', 0);        $ex->setOrder('`timestamp` DESC');        $ex->setLimitClause($first, $count);
        return $this->findListByExample($ex);    }
    public function countUserArticleByPeriod( $id, $lb, $ub )    {        $ex = new OW_Example();        $ex->andFieldEqual('authorId', $id);        $ex->andFieldBetween('timestamp', $lb, $ub);        $ex->andFieldEqual('isDraft', 0);        $ex->setOrder('`timestamp` DESC');
        return $this->countByExample($ex);    }
    public function findList( $first, $count, $optionalParmams = array(), $order )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $ex = new OW_Example();        $ex->andFieldEqual('isDraft', 0);        $ex->andFieldEqual('privacy', 'everybody');        foreach ($optionalParmams as $key => $value){        $ex->andFieldEqual($key, $value);        }        $ex->setOrder($order)->setLimitClause($first, $count);
        $cacheLifeTime = self::CACHE_LIFE_TIME;        $tags = array( self::CACHE_TAG_ARTICLE_COUNT );
        return $this->findListByExample($ex, $cacheLifeTime, $tags);    }
    public function findTopRatedList( $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $query = "SELECT p.*, IF(SUM(r.score) IS NOT NULL, SUM(r.score), 0) as `t`FROM `{$this->getTableName()}` as pLEFT JOIN `". OW_DB_PREFIX ."base_rate` as r /*todo: 8aa*/ON( r.`entityType` = 'article-article' AND p.id = r.`entityId` )WHERE p.isDraft = 0GROUP BY p.`id`ORDER BY `t` DESCLIMIT ?, ?";
        return $this->dbo->queryForObjectList($query, $this->getDtoClassName(), array($first, $count));    }
    public function findListByTag( $tag, $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }
        $query = "SELECT p.*FROM `". OW_DB_PREFIX ."base_tag` as tINNER JOIN `". OW_DB_PREFIX ."base_entity_tag` as `et`ON(`t`.`id` = `et`.`tagId` AND `et`.`entityType` = 'article-article')INNER JOIN `{$this->getTableName()}` as pON(`et`.`entityId` = `p`.`id`)WHERE p.isDraft = 0 AND `t`.`label` = '{$tag}'ORDER BY `t`.`id` DESCLIMIT ?, ?";
        return $this->dbo->queryForObjectList($query, $this->getDtoClassName(), array($first, $count));    }    public function findListByTags( $tags, $first, $count )    {        if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }                $query = "SELECT DISTINCT p.*FROM `". OW_DB_PREFIX ."base_tag` as tINNER JOIN `". OW_DB_PREFIX ."base_entity_tag` as `et`ON(`t`.`id` = `et`.`tagId` AND `et`.`entityType` = 'article-article')INNER JOIN `{$this->getTableName()}` as pON(`et`.`entityId` = `p`.`id`)WHERE p.isDraft = 0 AND `t`.`label` in ({$tags})ORDER BY `t`.`id`LIMIT ?, ?";        return $this->dbo->queryForObjectList($query, $this->getDtoClassName(), array($first, $count));    }
    public function countByTag( $tag )    {        $query = "SELECT count( * )FROM `". OW_DB_PREFIX ."base_tag` as tINNER JOIN `". OW_DB_PREFIX ."base_entity_tag` as `et`ON(`t`.`id` = `et`.`tagId` AND `et`.`entityType` = 'article-article')INNER JOIN `{$this->getTableName()}` as pON(`et`.`entityId` = `p`.`id`)WHERE p.isDraft = 0 AND `t`.`label` = '{$tag}'";
        return $this->dbo->queryForColumn($query);    }
    public function findListByIdList( $list )    {        $ex = new OW_Example();
        $ex->andFieldInArray('id', $list);        $ex->andFieldEqual('privacy', 'everybody');
        $ex->setOrder('timestamp DESC');
        return $this->findListByExample($ex);    }
    public function updateArticlesPrivacy( $authorId, $privacy )    {        $this->clearCache();
        $sql = "UPDATE `" . $this->getTableName() . "` SET `privacy` = :privacy            WHERE `authorId` = :authorId";
        $this->dbo->query($sql, array('privacy' => $privacy, 'authorId' => $authorId));    }public function getFeaturedArticleList($first, $count) {if ($first < 0)        {            $first = 0;        }
        if ($count < 0)        {            $count = 1;        }$query = 'SELECT `a`.*                    FROM `' . $this->getTableName() . '` AS `a`                        INNER JOIN `' . ARTICLES_BOL_ArticleFeaturedDao::getInstance()->getTableName() . '` AS `f` ON (`f`.`articleId`=`a`.`id`)                    ORDER BY `a`.`id` DESC                    LIMIT ?, ?';return $this->dbo->queryForObjectList($query, $this->getDtoClassName(), array($first, $count));}    public function clearCache()    {        OW::getCacheManager()->clean( array( ARTICLES_BOL_ArticleDao::CACHE_TAG_ARTICLE_COUNT ));    }}