if (!isset($this->Fields[$field]) && $field != 'RAND()' && !$is_expression) {
trigger_error('<span class="debug_error">Incorrect sorting</span> defined (field = <b>'.$field.'</b>; direction = <b>'.$direction.'</b>) in config for prefix <b>'.$this->Prefix.'</b>', E_USER_WARNING);
trigger_error('<span class="debug_error">no filters defined</span> for prefix <b>'.$this->Prefix.'</b>, but <b>DrawFilterMenu</b> tag used', E_USER_WARNING);