apache exits on signal 4

[dave]

Hello,
    Fbsd 5.3-RELEASE, apache 2.53, php4 installed. Everything was working
than i got a report of site's being down. I investigated and learned that
apache was not starting. I tried a restart, which did not produce an error,
however checking for an http process ID didn't show anything. I then checked
/var/log/messages and /var/log/httpd-access.log and found that the apache
startup was dying on a signal 4. Googling on this did not tell me what it
was or more importantly how to fix it.
    Any info appreciated.
Thanks.
Dave.