Same problem – spinning icon when I try to add a friend.
PHP Version=5.2.9. Just installed BuddyPress and MU for first time today (May 3, so I think I have BuddyPress 1.0). Hosting at HostNine.com with typical CPanel.
Website with issue: http://3wcloud.com/wordpressmu. I have turned on the ability to add new users if you want to see what is happening.
