I found it in /tmp. Sorry for not finding it earlier...
tail /tmp/install.log.31931:
Code:
(Reading database ... 55383 files and directories currently installed.)
Preparing to replace zimbra-core 5.0.16_GA_2921.UBUNTU8 (using .../zimbra-core_5.0.18_GA_3011.UBUNTU8_i386.deb) ...
Unpacking replacement zimbra-core ...