Activation Code invalid

I tried to set up my subscription on my MacBookAir but am being given a notification that the activation code is invalid. It was purchased on the military base so it was a box with a piece of paper in it with an activation code and instructions. I tried to enter the code on the "form" for invalid codes on the avg activation website but it just takes me to a page for downloading apps.

Hello Mykaela,

We will help you in this.
You have to register the Code with AVG when it is bought from a re-seller.
Refer this article for the steps to register the Product Key with AVG :
https://support.avg.com/SupportArticleView?urlname=AVG-Register-product-retail-reseller
Let us know if you need any help.