I have exactly the same problem right now.
copying emails from a local .pst file to zimbra works..but they are not on the zimbra server

only in the local .zdb fileset.
I tried that with another machines - with the same (bad) result.
maybe someone can reproduce the problem on his workstaton too?
-> just copy emails from a pst file (create a pop3 account for example) and move them to teh zimbra account
copying emails from an external imap account to zimbra works via outlook - emails are also accessable via the webinterface.
copying emails from teh .pst file to the imap account an then to zimbra..works lol
zimbra server: 6.0.7_GA_2476.RHEL4 (01.com hosting server) client: outlook 2010, win7 64bit, zco: 6.0.6089.9
Outlook 2010 Import Issues [Outlook 2010 Import Issues] seems that my hunch is right - outlook user can not be sure, that there emails are really on the zimbra server