Did you check that LDAP was actually stopped after this upgrade failed? Can you see if it's still there (and any other zimbra processes), if it is still active then kil the processes and do the upgrade again.
I'm slightly confused as to which version of Zimbra you're referring, the current GA build is 3.0.1 - are you upgrading to that release? If so which version are you upgrading from?
There's also
this page in the wiki for troubleshooting LDAP problems.