For those of you looking for an answer to this problem, I can offer some help. After working on this for HOURS today, I have determined that my RPM installation of Apache and PHP is the root of my issues.

The problem is likely related to PHP's compilation. After reading about this the most commonality I discovered is related to XML. It must be switched on properly when PHP is compiled. A default install of Redhat 9 Server does not compile PHP with this switch. See the following link:

http://www.vbulletin.com/forum/showthread.php?t=98665

Anyway, I ended up following the instructions on this site and totally abandoning the default install of Apache & PHP. Here's the details:

Download PHP. Put in /usr/local/src

cd /usr/local/src/php-xxx
./configure --prefix=/usr/local/php --with-config-file-path=/usr/local/php --with-mysql --with-apache=../apache_xxx --enable-track-vars --enable-debugger --enable-magic-quotes --with-xml=shared
make
make install
Note: The vBulletin install manual does NOT include "--with-xml=shared" at the end of the ./configure command above. I added that portion after finding it on this forum. Someone should really tell them to modify their manual. It sucks for that reason.

Anyway, download the latest Apache 1.x. I haven't done Apache 2.x... there is no help for it in the manual either. For that reason, I stick to 1.x... Put it in /usr/local/src.

cd /usr/local/src/apache_xxx
./configure --prefix=/usr/local/etc/httpd --activate-module=src/modules/php4/libphp4.a
make
make install
Go to /usr/local/etc/httpd/bin and run ./apachectl start
You will no longer use "service httpd start"

The script should work...