The problem is you've had a corrupt install and the saved LDAP data is invalid. I suggest you uninstall ZImbra by running './install.sh -u' the deleting the /opt/zimbra directory, when you've done that run the install again.
Check your configuration is OK by running the following (before you do the install)::
Code:
host `hostname` <-- backticks not single quotes
dig yourdomain.com any
dig yourdomain.com mx
if you don't understand the output then post the details.