chenz, the register-plugin app isn't mentioned in that logfile at all; /serengeti and /datadirector are the only ones mentioned. I tried /serengeti/register-plugin and /datadirector/register-plugin and no dice.
Yonghua, there weren't any errors during boot, just a warning about some chef option being deprecated.
I searched the serengeti logs directory and the tomcat logs directory for 'register' and only came up with a few hits, ignoring the Hibernate thing that isn't found in serengeti.log.
/opt/serengeti/logs/serengeti-firstboot.log: registering serengeti server as vc ext service
/opt/serengeti/logs/serengeti-firstboot.log:[21-Aug-2013 18:15:35] DEBUG VcExtension:92 - Registering extension vService at: https://vcenter.concord.local/vsm/extensionService ExtensionKey: com.vmware.serengeti.b238f66a
/opt/serengeti/logs/serengeti-firstboot.log:[21-Aug-2013 18:15:35] DEBUG VcExtension:140 - Successfully registered
Searching /opt/serengeti/tomcat6/logs/ results in 'SEVERE' notices that "The web application [/serengeti] registered the JDBC driver but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered." The same notice appears for /datadirector.
The word 'register' does not appear elsewhere in any file in either directory
Just to make sure I didn't stumble across some old page, The OVA I have is "VMware-Serengeti-0.8.0.0-1063738_OVF10.ova"