For accounts created via the "register" screen (rather than the "facebook 1-click" button), after the account is created the user is taken to a screen which says something like "Congratulations, you're done! Set up your avatar?" But actually the user is NOT finished... the user MUST go to their email and click a special link to authenticate the account. And in fact the avatar-editing won't work until they do that.
Probably best will be to skip over this page, or second-best would be to adjust the copy so that it's not so misleading.