Let me explain my scenario first.

One of our clients wants to re-install their Zimbra server and upgrade the O.S and ZCS as well.

Old Server : Ubuntu 6.06 LTS Server
ZCS 5.0.4_GA_2101

New Server : Ubuntu 8.04 LTS Server
ZCS 5.0.16_GA_2921

So far i have a good backup of the server and im trying to restore it to another server just as a test run.

I followed the instructions on
Moving ZCS to New Server - Zimbra :: Wiki

so anyway i put the dummy copy of zimbra onto the new server.
restore my zimbra backup
run zmfixperms
run the install.sh again.

Everything loads fine until it gets to

Verifying /opt/zimbra/conf/my.cnf
Starting mysql
At this point it just hangs and does nothing...

If i kill this install, then try start mysql manually using

root@zimbra:/opt/zimbra/bin# ./mysql start
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/opt/zimbra/db/mysql.sock' (2)
i checked permissions to /opt/zimbra/db

they belong to the user zimbra on both servers...

My question is....can this upgrade be done?

If yes, what am i doing wrong?