in version 8.0.3 to 8.0.4 update the error is:

Shutting down zimbra mail

Backing up the ldap database...done.

Removing existing packages

zimbra-ldap...done
zimbra-logger...done
zimbra-mta...done
zimbra-snmp...done
zimbra-store...done
zimbra-spell...done
zimbra-apache...done
zimbra-core...done

Removing deployed webapp directories
Installing packages

zimbra-core......zimbra-core-8.0.4_GA_5737.RHEL6_64-20130524120036.x86_64.rpm...FAILED
###ERROR###

zimbra-core-8.0.4_GA_5737.RHEL6_64-20130524120036.x86_64.rpm installation failed

Installation cancelled

tnk

Marcelo Rolin