apache and php strangeness

[Johan Booysen]

I have a strange problem that I haven't been able to solve:
 
We have 2 internal web sites (developed using PHP) running on a RHEL5 server.  Each and every time, without fail, when the server is rebooted, you browse to those sites and get a 500 Internal Server Error message.  The only way I've found that "fixes" it on the short term is to do:
 
killall httpd
apachectl -k restart
 
A regular "service httpd restart" doesn't do the trick.
 
Can anyone perhaps give me a clue as why this might be?  It's not a huge problem and those sites aren't mission-critical, but it would be nice to know why I'm getting this behaviour.
 
Thanks very much.