Firstly I would recommend upgrading at some point. Secondly, try shutting it down and starting using the /etc/init.d/zimbra script instead to see if that makes a difference. Also make sure that all ZCS processes have indeed died prior to restarting ZCS.
Something like the following would kill of any old processes nicely after the zmcontrol stop
Code:
ps -u zimbra -o pid | xargs -i kill {}