Sorry, don't know what's wrong but it's an odd fault. When I click on Chatterbank your avatar ( HMS resolution emblem ) is there. It's also there when I click on it but if I click on the thread it disappears. Suggest you contact Ed.
Squad:
The avatars displayed on this site aren't stored on AB's servers. Instead they're called up from the servers of Gravatar, using a member's email address to identify them. (So if someone signs up to several different sites using the same email address, and they all use Gravatar to source avatars from, he/she will find that the same avatar appears on all of the sites).
Gravatar is now part of Wordpress, so you need a Wordpress account to log in and get yourself an avatar.