strtotime()で警告メッセージ

PHP Warning: strtotime(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Asia/Tokyo' for 'JST/9.0/no DST' instead in /var/www/html/blog/wp-content/themes/lumiukko/make_ranking_inboundlink.php on line 16 /etc/php.iniファイルを編集。

[Date]
; Defines the default timezone used by the date functions
; http://www.php.net/manual/en/datetime.configuration.php#ini.date.timezone
date.timezone = "Asia/Tokyo"