Can't change a userpic

Users--admin included--can't change the userpic from the edit profile form. You can upload one, but then you can only delete it. Trying to upload a new one just keeps the old one, or, if the user deletes the pic first, reassigns the old one back.

I'm using a custom theme, Drupal 6.13.

Website is http://www.hoperenews.org.