Just an FYI. At the end of the installation you are given the option to notify Zimbra. The URL used results in a 404 error.
http://www.zimbra.com/cgi-bin/notify...n@mydomain.com
I guess this is either an install script bug or the webmaster has dropped the ball
BTW - 5.0.9 on Ubuntu 8.04LTS upgraded from 5.0.6 without a hitch
Keep up the good work people!!