When attempting to add or remove AP databases with the apdb command, you can
get the error:

apdb: Resource temporarily unavailable

If you check in /var/adm/messages you find the reason:

Jan 15 14:00:51 Starfire2 apd[683]: /etc/system: could not find:
                                    * End AP database info (do not edit)
Jan 15 14:00:52 Starfire2 apd[683]: failed to patch the system file!


Unfortunately, this error does not get echoed to the console (netcon session);
so. it can easily be missed.

To fix, simply edit the /etc/system file so that it has the correct comments
before and after setting ap:apdb_dblist. E.g.

* Begin AP database info (do not edit)
set ap:apdb_dblist="sd:5 sd:8"
* End AP database info (do not edit)