So, I had a problem with migration from one server to another.
This is how I solved this problem:
1. backup /opt/zimbra/backup & /opt/zimbra/storage
2. install zimbra 4.0.5 and configure it properly
2.1. if you had multiple domains, create those domains on new server before doing enything else
3. copy backup & storage folders of old server to new one into same location
4. switch to zimbra user by typing "su zimbra"
5. type "cd /opt/zimbra/backup"
6. then type "zmrestoreldap -lb label_name_goes_here" for example "full-20061207.050018.654"
7. then you can type "zmrestoreoffline -a all" it will restore all acoounts and mailboxes
7.1. In case if you had all accounts restored but no mails in it, you have to restore eache account manually, i.e. "zmrestoreoffline -a firstname.lastname@example.org"
8. When you will complete all the steps start zimbra by typing "zmcontrol start"
That's it. Hope this topic will help to someone.