Solaris 8 and later versions should not need pt_cnt. Ptys should be dynamically allocated as needed. Can you describe the problem you are having?
See the Solaris 2 FAQ:
http://www.science.uva.nl/pub/solaris/solaris2.html#q5.30
5.30) I get Could not grant slave pty on telnet/rlogin
In Solaris 8 and later you must make sure you have syseventd/devfsadmd running or the automatic pty node creation does not work.
In older releases this probably means that you changed "pt_cnt" but didn't reboot with the "-r" flag. To recover, run "drvconfig; devlinks".
So, you should make sure syseventd and devfsadmd are running.
--
Darren