You appear to be installing packages on a platform different
than the platform for which they were built.
This platform is CentOS5_64
Packages found: RHEL6_64
This may or may not work.
Using packages for a platform in which they were not designed for
may result in an installation that is NOT usable. Your support
options may be limited if you choose to continue.
Install anyway? [N] y
The system will be modified. Continue? [N] y
Shutting down zimbra mail
Removing existing packages
Removing deployed webapp directories
zimbra-core-7.1.2_GA_3268.RHEL6_64-20110804131406.x86_64.rpm installation failed