Game Sync Code issue

[MangaDragon]

(I haven't posted anything on here in a long time....)

Last night I finally got back to the Global Link website and when I tried to get my Chimchar and Zekrom back the games had a new Game Sync code and wanted me to register them.

Can anyone explain what this means or what I should do?
I tried asking a question on the website already. The button to send the message never appeared.