error show on header admin page

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/virtual/site20/fst/var/www/html/mydomain/cms/kb5/class/Database.Class.php on line 22

example ::




koobi pro 5.7

Database.Class.php on line 22 :::

function FetchArray()
{
return mysql_fetch_array($this->_result);
}



use MySQL 3.23.58