1.3.27 core dumps if PHP4 module is loaded.

I am running FreeBSD 5.1, Apache 1.3.27 (installed from package), and
mod_php4-4.3.1,1 compiled from ports, as well the various other things
necessary to install and run Horde with IMP, Turba, and Kronolith, all
compiled from ports.

I have noticed over the last couple of days that my server begins to
act finicky (not displaying the pages, or not processing logins
requests). If I attempt to restart apache, it complains either of
errors in mod_php4, or lately, simply prints:

Bus error (core dumped)
/usr/local/sbin/apachectl start: httpd could not be started

If I comment out the LoadModule and AddModule lines for php4 in
httpd.conf the server loads properly. If I reboot the server it also
loads and runs properly for several hours.

Any ideas?

Best,
Thomas