OS is debian Ver 4.0 while Upgrading from 5.0.11_GA OPEN SOURCE
to 5.0.18, with the package downloaded from:
http://h.yimg.com/lo/downloads/5.0.1...0707170635.tgz

the upgrade process get's me to the configuracion with a message:

******* +License filename: UNSET
Address unconfigured (**) items

and i can not go any further. i've canceled the installation and restart the server
it appears to be running ok...

the install log shows this:
Sun Jul 26 12:35:19 2009 zimbra-proxy is not enabled
Sun Jul 26 12:35:19 2009 *** Running as zimbra user: /opt/zimbra/bin/zmlicense -c: No such file or directory