This issue has been resolved. It will now be possible to create a new character without changing the account PIC. Thank you for your patience.
The MapleStory team is investigating an issue that may prevent players from creating a new character if the account's Personal Identification Code (PIC) has not been changed recently.
This affects accounts that receive the message "You have not changed your PIC in a while. Would you like to now?" when logging in to a character. Creating a new character and selecting the "No" option will log in to another character on the account rather than bring up the character creation screen.
We hope to have this issue resolved as soon as possible. As a work-around, click Yes to change the PIC. Once a new PIC has been established, it will be possible to create a new character like normal.
Website Announcement: http://maplestory.nexon.net/news/54265/issue-with-character-creation
We apologize for the inconvenience and appreciate your patience!