I am playing with Gallery3 on Debian Squeeze. When I try to upload files through the Gallery3 interface I see the error of:
Error: your server is configured to use the suhosin.session.encrypt setting from Suhosin. You must disable this setting to upload photos
Normally, I would ask the Gallery3 for support but since Debian likes to tweak the packages of the apache2 web server package I am not entirely sure where to start.