It would be nice to post a url to your site to test
Okay well I can only guess but try a couple of items.
Control Panel » Profile Settings
Avatars
Avatar Upload Storage Directory:
This setting is only needed if members can upload avatar.
(Click to test directory.)
Full URL to Avatar Upload Storage Directory:
This setting is only needed if members can upload avatar.
Make sure to click on the test link!!
Then check:
Control Panel » Site Permissions
Can specify a remote avatar
Add a 1 for the groups in question
And select submit at the bottom of the page
This is probably your issue!
