My website no shows default avatars.

Hi: I went up on my website with a simple theme wordpress Blogsmu. I do not have a multisite but I have ten sites associated with a website.
I install "buddypress", "members directory", "avatars" and "friends". These plugins do not show default avatars. Only Gravatar (wordpress.com) Sorry I don't speak english.
I need your help.
Thank you.
Grace