I successfully installed 5.0RC2. The installation went smooth. Everything seems to look fine.
I tried to use the caldav freature. http://Servername/dav/username and got the message "... Domain (null)/Error" when trying tu add Zimbra to the ical 3.0 Server (1.5.1 German).
I suppose it is a Leopard problem as I get the same message with DAViCal and other clients. But I could be wrong.
Thank you in advance