Warning: arraymap() expects parameter 1 to be a valid callback, class 'TypechoJson' not found in /mnt/sdcard/www/var/Json.php on line 243

Warning: Invalid argument supplied for foreach() in /mnt/sdcard/www/var/Json.php on line 245

Warning: join(): Invalid arguments passed in /mnt/sdcard/www/var/Json.php on line 252

环境是openwrt+uhttpd+php+mysql。
什么地方出了问题？

php代码：
// treat it like a regular array

            $elements = array_map(array('Typecho_Json', '_encode'), $var);

            foreach ($elements as $element) {
                if (self::_is_error($element)) {
                    return $element;
                }
            }

            return '[' . join(',', $elements) . ']';