I just updated both my Avatar and Signature settings, both the Offline and Online items, and they both Saved each time. Producing the "Saved" red letter text. I used Google Chrome and IE 8, logged in, made changes, saved, logged out, cleared cookies, closed Browser, started over and Logged in, my changes were still there.
Can you please tell me if you have tested this after clearing your cookies, and in which Browser(s) you are using?