Cannot Register for Mac

I cannot register avast for my mac book pro. Definitions update ok. When I click on register, which I have done 2x with different email addresses, it takes me directly to the register window. Then the days left to register countdown begins. My version is 10.6.8. I have uninstalled and re-installed. Same problem.
I have registered and received a license key.
Where do I install the license key? No link under maintenance. Avast version 7.0 (37264)

OK support says I do no t need a license key or activation code. Just register online. Still see the countdown of days left to register under maintenance link.
Thanks