I am now having the same issue. My system locked up last night, so I had to power cycle this morning. After the power cycle, I can't get zdesktop to run.
I tried a re-install, and the installer says it can't run because zdesktop is still running, which it isn't.
So, I moved my old zimbra out of the way, and installed from scratch. I then moved derby, store, index, redolog, and log into the new zimbra. The problem comes up again.
Normally this wouldn't be an issue, but I was forced to move my email to local storage folders indetad of IMAP folders (long story), and I don't want to lose all my emails.
My zdesktop.out file wouldn't upload, too big. Here's a copy/paste of what I think may be important:
I'm with out email now, and in serious trouble.
Thu Feb 26 10:12:38 CST 2009: error communicating with LDAP (will retry)
com.zimbra.common.service.ServiceException: system failure: ZimbraLdapContext