Astrisk restart automatically

I have Asterisk 1.4.14 with g723 and g729 installed and h323 module.
I start it with “safe_asterisk -vvvvvg” but I see it restarted in some hours(2-3 hours).
I could not find core dumped log in /tmp/ , and my system is RHE 4 .
I would be so pleased if you could help me on this.

Set the verbosity and debug levels to 9 and set logger.conf to log everything. When it does restart have a look in the logs. Also monitor the CPU usage. I have seen that when it gets too high for the machine asterisk can restart.