For those interested after reading my previous post, the following behavior is observed:
If Patch Solaris Patch 119213-19 is applied before Sun Directory Server 5.2 is installed, you will observe that the Administration Server was successfully installed.
But in actual fact, when you look at the installed directory, the "admin-serv" sub-directory is not created. The "start-admin" script is also not created.
In short, the Administration Server was not successfully installed as opposed to what was reflected by the installer.
I did some debugging and found out that prior to the installation of the Administration Server, the Configuration LDAP "slapd-config" was first created. When the installation of the Administration Server run, it tried to contact the Configuration LDAP.
But, of course, it hit the "Invalid Credential" issue (caused by the NSS 3.1.2). Thus the Administration Server never get installed at all.