problem to restart services from /etc/inittab in AIX6.1

hello,
i have an AIX6.1.7.2 machine that it was upgraded recently from AIX5.3.9.4.
when i kill system services that should restart automatically like /usr/sbin/cron it doesnt start.
i checked my /etc/inittab file and i confirmed that this service is in respawn status so when i kill this process it should automatically start again. i have the same problem with other services located in /etc/inittab also.
if i run the process manually it starts but if i just kill it and wait to restart automatically by /etc/inittab it does nothing.
what might be the cause of it and how i can solve it?

thank you

Have you been running "telinit q" ?

yes i already tried it but nothing happens