Hello Paul.
I am not familiar with Korean (maybe some day ) but I think this can be a locale problem.
Do you have Korean locale installed in your server? I had to install the Spanish locale in my Debian Linux box to show months correctly in Moodle. This value is taken directly from system date and locale settings of your server. I guess '월' is a month name, does not it?
Try my suggestions, find some help out there or search into forums for this issue.
Good luck.