In order to receive support for the Theme Blvd themes purchased over on ThemeForest, you'll need to register here for an account to gain access to the forums.
After registering, you'll then need to login and add your Envato purchase codes at My Account > Licenses. This will give you access to the forums that correspond to your registered purchases.
Are you a Jump Start customer?
If you've made a purchase from wpjumpstart.com, you already have an account here and will have automatic access to the Jump Start forum. Simply login with the username you created when you checked out at wpjumpstart.com.
Additionally, any ThemeForest purchases you've made can be added onto your current account after logging in.