Your site has a nagging My Account link on all pages which is only for registered users of Axure Portal, but not for Axure Community users. If I have logged into Axure community and mistakenly click on My Account I'm asked for a user name and password. And this username and password are completely different from what I just used to Sign in on Axure Community. Could you please make users of Axure Portal also default users for Axure Community. In this world of username's and password's, the last thing you want is two different sets of these for the same site but different sections.
Sorry to be nagging but even the most intelligent land up making stupid mistakes and it would be better if you create a seamless user experience. Please don't assume your users will figure it out.