When you look on My Profile, Edit User Details does it say you avatar is active?
Clear your cache- if on IE log out of AB, use Tools, Internet options, delete, delete... Log back in...
Tools> Internet options> delete> (tick all the boxes)>delete
That's how to clear teh cache. It's a good idea to log out of AB first then log back in after.
When you go on my Profile, Edit User Details is the box ticked to show your avatar is active? If not then you need to tick the box. If you can't see it just click on the line- over the letters YO is best.
Is your Avatar passowrd the same as your AB password?