I have downloaded and experimented with the language pack you showed me.
To display the month properly if your Zen Cart runs on a Windows machine, your "schinese.php" file could have the following settings.
PHP Code:
setlocale(LC_ALL, 'Chinese_China.936');
PHP Code:
define('HTML_PARAMS','dir="ltr" lang="zh"');
PHP Code:
define('CHARSET', 'Windows-936');
Unfortunately, once your month displays properly, your browser may display the rest of the characters incorrectly due to the encoding that was used to edit the translated files. You may like to contact the language pack author and discuss with him/her on the best approach for your case - taking into consideration the possibility that your live Zen Cart store will be running on a Linux/Unix machine instead of a Windows machine.
Alternatively, you can download and install the Simplified Chinese language pack in the downloads section on top of an existing English installation. That language pack is for GB2312 but you can adjust the "schinese.php" file with the above settings and see if it meets your needs assuming you are running on a Windows machine.