I've been asked to post a clarification:
You cannot patch Solaris 10 from Solaris 8 or 9 as the version of 'patchadd' in Solaris 8 and 9 is totally unaware of how to handle Zones and other Solaris 10 specific features.
If using Live Upgrade to upgrade an inactive boot environment from Solaris 8 or 9 to Solaris 10, you must activate and boot into the Solaris 10 boot environment before patching it. For example, activate and boot into the Solaris 10 boot environment, and either patch the live boot environment or create another inactive boot environment, and then apply patches to the inactive boot environment.
See http://www.sun.com/bigadmin/features/articles/live_upgrade_patch.jsp for further information.