note, that this is used by Redhat (and derivatives). debian use 0,1, and 6 from this, and have "2" as everything. 3,4 and 5 are unused.
Any unused runlevels can be tailored to your own needs.
lib/main.php:944: Notice: PageInfo: Cannot find action page
lib/main.php:839: Notice: PageInfo: Unknown action
lib/plugin/WlugLicense.php:99: Warning: Invalid argument supplied for foreach()