No, you do not have to make an account. You simply click on the Adoptables tab under the site banner, then click on the pet you want. Copy and paste your code to adopt the pet ^-^
Next time, please ask your questions on the sites thread before making a new thread, okay? Here is the link to the thread made by Malk:
viewtopic.php?f=11&t=547&start=0Locking.