I've never seen that error, but I would note three things:
a) 32-bit platforms are EOL. I.e. there is no support for any 32-bit platforms after ZCS7.
b) RHEL5 is EOL. I.e., there is no support for RHEL5 after ZCS7.
c) You do not give any information about what Zimbra build you tried to install. Perhaps you downloaded a build for a platform other than the one you are installing on.
If you are looking at setting up a new installation, I would strongly advise you to use a supported platform for ZCS8: RHEL6 64-bit, UBUNTU12 64-bit, or SLES11 64-bit.
Hope that helps,
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