Blog & User Avatar Upload Error

HI,

When I upload my avatar and try to crop it, the page refreshes, an outline of the avatar flashes and then disappears. Avatar then does not show up on site. Alternate upload does the same thing.

MU was setup by wp.mu, so I imagine everything was setup right with the plugin installed. In fact, I checked, and the avatar/blog & user directories are there and permissions are set.

Any ideas?

Thanks,
Gray