He installed some software that affects threading and it's likely other things (that he didn't notice yet) are also affected. It's still weird, though. If you do not overwrite any base files you won't hit this problem.
Woah.
Well, here's where I disagree What's non standard in my install other than PHP? Furthermore, uninstalling PHP does nothing?
I submit yum.log for further scrutiny. Note the part where I removed PHP and the problem still persisted.
Oct 03 20:13:12 Installed: nano.i386 1.3.12-1.1 Oct 03 20:28:42 Installed: make.i386 1:3.81-3.el5 Oct 03 20:29:58 Updated: libgcc.i386 4.1.2-42.el5 Oct 03 20:30:04 Updated: glibc-common.i386 2.5-24 Oct 03 20:30:10 Updated: glibc.i686 2.5-24 Oct 03 20:30:10 Installed: glibc-headers.i386 2.5-24 Oct 03 20:30:10 Installed: glibc-devel.i386 2.5-24 Oct 03 20:30:10 Installed: binutils.i386 2.17.50.0.6-6.el5 Oct 03 20:30:10 Installed: cpp.i386 4.1.2-42.el5 Oct 03 20:30:10 Installed: libgomp.i386 4.1.2-42.el5 Oct 03 20:30:11 Installed: gcc.i386 4.1.2-42.el5 Oct 03 20:39:36 Updated: bash.i386 3.2-21.el5 Oct 03 20:39:36 Updated: chkconfig.i386 1.3.30.1-2 Oct 03 20:39:36 Updated: popt.i386 1.10.2-48.el5 Oct 03 20:39:36 Updated: audit-libs.i386 1.6.5-9.el5 Oct 03 20:39:36 Updated: bzip2-libs.i386 1.0.3-4.el5_2 Oct 03 20:39:39 Updated: perl.i386 4:5.8.8-15.el5_2.1 Oct 03 20:39:39 Updated: libacl.i386 2.2.39-3.el5 Oct 03 20:39:40 Updated: libxml2.i386 2.6.26-2.1.2.6 Oct 03 20:39:40 Updated: freetype.i386 2.2.1-20.el5_2 Oct 03 20:39:40 Updated: libpng.i386 2:1.2.10-7.1.el5_0.1 Oct 03 20:39:40 Updated: libstdc++.i386 4.1.2-42.el5 Oct 03 20:39:40 Updated: libtiff.i386 3.8.2-7.el5_2.2 Oct 03 20:39:40 Updated: pcre.i386 6.6-2.el5_1.7 Oct 03 20:39:40 Updated: procps.i386 3.2.7-9.el5 Oct 03 20:39:40 Installed: nspr.i386 4.7.1-1.el5 Oct 03 20:40:11 Installed: nss.i386 3.12.1.1-1.el5.centos.1 Oct 03 20:40:11 Updated: file.i386 4.17-13 Oct 03 20:40:11 Updated: gnutls.i386 1.4.1-3.el5_1 Oct 03 20:40:11 Updated: cups-libs.i386 1:1.2.4-11.18.el5_2.1 Oct 03 20:40:11 Updated: tcp_wrappers.i386 7.6-40.4.el5 Oct 03 20:40:12 Updated: libX11.i386 1.0.3-9.el5 Oct 03 20:40:12 Updated: diffutils.i386 2.8.1-15.2.3.el5 Oct 03 20:40:12 Updated: iproute.i386 2.6.18-7.el5 Oct 03 20:40:12 Updated: pkgconfig.i386 1:0.21-2.el5 Oct 03 20:40:12 Updated: centos-release-notes.i386 5.2-2 Oct 03 20:40:12 Updated: centos-release.i386 10:5-2.el5.centos Oct 03 20:40:12 Updated: cracklib-dicts.i386 2.8.9-3.3 Oct 03 20:40:12 Updated: libxslt.i386 1.1.17-2.el5_2.2 Oct 03 20:40:13 Updated: kernel-headers.i386 2.6.18-92.1.13.el5 Oct 03 20:40:13 Installed: keyutils-libs.i386 1.2-1.el5 Oct 03 20:40:13 Updated: bzip2.i386 1.0.3-4.el5_2 Oct 03 20:40:13 Updated: iptables.i386 1.3.5-4.el5 Oct 03 20:40:13 Updated: gzip.i386 1.3.5-10.el5.centos Oct 03 20:40:13 Updated: telnet.i386 1:0.17-39.el5 Oct 03 20:40:14 Updated: man-pages.noarch 2.39-10.el5 Oct 03 20:40:14 Updated: tzdata.noarch 2008e-1.el5 Oct 03 20:40:14 Updated: traceroute.i386 3:2.0.1-3.el5 Oct 03 20:40:15 Updated: libselinux.i386 1.33.4-5.el5 Oct 03 20:40:15 Updated: coreutils.i386 5.97-14.el5 Oct 03 20:40:18 Updated: python.i386 2.4.3-21.el5 Oct 03 20:40:18 Updated: pam.i386 0.99.6.2-3.27.el5 Oct 03 20:40:18 Updated: shadow-utils.i386 2:4.0.17-13.el5 Oct 03 20:40:18 Updated: newt.i386 0.52.2-10.el5 Oct 03 20:40:18 Updated: device-mapper.i386 1.02.24-1.el5 Oct 03 20:40:18 Updated: e2fsprogs-libs.i386 1.39-15.el5 Oct 03 20:40:19 Updated: openssl.i686 0.9.8b-10.el5 Oct 03 20:40:19 Updated: krb5-libs.i386 1.6.1-25.el5 Oct 03 20:40:19 Updated: openldap.i386 2.3.27-8.el5_2.4 Oct 03 20:40:19 Updated: util-linux.i386 2.13-0.47.el5 Oct 03 20:40:19 Updated: psmisc.i386 22.2-6 Oct 03 20:40:19 Updated: libuser.i386 0.54.7-2.el5.5 Oct 03 20:40:20 Updated: samba-common.i386 3.0.28-1.el5_2.1 Oct 03 20:40:20 Updated: postgresql-libs.i386 8.1.11-1.el5_1.1 Oct 03 20:40:20 Updated: apr-util.i386 1.2.7-7.el5 Oct 03 20:40:20 Updated: bind-libs.i386 30:9.3.4-6.0.2.P1.el5_2 Oct 03 20:40:22 Updated: fontconfig.i386 2.4.1-7.el5 Oct 03 20:40:22 Updated: cracklib.i386 2.8.9-3.3 Oct 03 20:40:22 Updated: usermode.i386 1.88-3.el5.1 Oct 03 20:40:22 Updated: e2fsprogs.i386 1.39-15.el5 Oct 03 20:40:22 Updated: audit-libs-python.i386 1.6.5-9.el5 Oct 03 20:40:22 Updated: libselinux-python.i386 1.33.4-5.el5 Oct 03 20:40:22 Updated: libxml2-python.i386 2.6.26-2.1.2.6 Oct 03 20:40:23 Updated: dbus.i386 1.0.0-7.el5 Oct 03 20:40:23 Updated: module-init-tools.i386 3.3-0.pre3.1.37.el5 Oct 03 20:40:23 Updated: net-tools.i386 1.60-78.el5 Oct 03 20:40:23 Updated: initscripts.i386 8.45.19.1.EL-1.el5.centos Oct 03 20:40:23 Updated: openssh.i386 4.3p2-26.el5_2.1 Oct 03 20:40:23 Updated: sysklogd.i386 1.4.1-44.el5 Oct 03 20:40:23 Updated: mcstrans.i386 0.2.7-1.el5 Oct 03 20:40:23 Updated: logrotate.i386 3.7.4-8 Oct 03 20:40:26 Updated: samba.i386 3.0.28-1.el5_2.1 Oct 03 20:40:26 Updated: httpd.i386 2.2.3-11.el5_1.centos.3 Oct 03 20:40:26 Updated: gd.i386 2.0.33-9.4.el5_1.1 Oct 03 20:40:26 Installed: yum-metadata-parser.i386 1.1.2-2.el5 Oct 03 20:40:26 Installed: python-iniparse.noarch 0.2.3-4.el5 Oct 03 20:40:26 Updated: httpd-manual.i386 2.2.3-11.el5_1.centos.3 Oct 03 20:40:27 Updated: samba-swat.i386 3.0.28-1.el5_2.1 Oct 03 20:40:27 Updated: vixie-cron.i386 4:4.1-72.el5 Oct 03 20:40:27 Updated: openssh-server.i386 4.3p2-26.el5_2.1 Oct 03 20:40:27 Updated: openssh-clients.i386 4.3p2-26.el5_2.1 Oct 03 20:40:27 Updated: authconfig.i386 5.3.21-3.el5 Oct 03 20:40:28 Updated: samba-client.i386 3.0.28-1.el5_2.1 Oct 03 20:40:28 Updated: sudo.i386 1.6.8p12-12.el5 Oct 03 20:40:28 Updated: fetchmail.i386 6.3.6-1.1.el5 Oct 03 20:40:28 Updated: m2crypto.i386 0.16-6.el5.2 Oct 03 20:40:28 Updated: tcpdump.i386 14:3.9.4-12.el5 Oct 03 20:40:28 Updated: ntsysv.i386 1.3.30.1-2 Oct 03 20:40:28 Updated: tar.i386 2:1.15.1-23.0.1.el5 Oct 03 20:40:28 Updated: rpm.i386 4.4.2-48.el5 Oct 03 20:40:29 Updated: rpm-libs.i386 4.4.2-48.el5 Oct 03 20:40:29 Updated: rpm-python.i386 4.4.2-48.el5 Oct 03 20:40:29 Updated: policycoreutils.i386 1.33.12-14.el5 Oct 03 20:40:29 Updated: bind.i386 30:9.3.4-6.0.2.P1.el5_2 Oct 03 20:40:29 Installed: yum-fastestmirror.noarch 1.1.10-9.el5.centos Oct 03 20:40:29 Updated: caching-nameserver.i386 30:9.3.4-6.0.2.P1.el5_2 Oct 03 20:40:29 Updated: yum.noarch 3.2.8-9.el5.centos.2.1 Oct 03 20:51:41 Installed: logwatch - 7.3-6.el5.noarch Oct 03 21:50:16 Installed: aspell - 12:0.60.3-7.1.i386 Oct 03 21:50:16 Installed: gmp - 4.1.4-10.el5.i386 Oct 03 21:50:16 Installed: php-common - 5.2.6-jason.1.i386 Oct 03 21:50:17 Installed: php-cli - 5.2.6-jason.1.i386 Oct 03 21:50:17 Installed: aspell-en - 50:6.0-2.1.i386 Oct 03 21:50:17 Installed: php - 5.2.6-jason.1.i386 Oct 03 21:56:43 Installed: php-mbstring - 5.2.6-jason.1.i386 Oct 03 21:57:59 Installed: php-bcmath - 5.2.6-jason.1.i386 Oct 03 21:59:03 Installed: php-pdo - 5.2.6-jason.1.i386 Oct 03 21:59:25 Installed: php-gd - 5.2.6-jason.1.i386 Oct 03 23:14:53 Installed: perl-DBI - 1.52-1.fc6.i386 Oct 03 23:14:54 Installed: mysql - 5.0.58-jason.2.i386 Oct 03 23:18:19 Installed: perl-DBD-MySQL - 3.0007-1.fc6.i386 Oct 03 23:18:20 Installed: mysql-server - 5.0.58-jason.2.i386 Oct 03 23:26:00 Installed: keyutils-libs-devel - 1.2-1.el5.i386 Oct 03 23:26:00 Installed: libsepol-devel - 1.15.2-1.el5.i386 Oct 03 23:26:00 Installed: libselinux-devel - 1.33.4-5.el5.i386 Oct 03 23:26:01 Installed: e2fsprogs-devel - 1.39-15.el5.i386 Oct 03 23:26:01 Installed: krb5-devel - 1.6.1-25.el5.i386 Oct 03 23:26:01 Installed: zlib-devel - 1.2.3-3.i386 Oct 03 23:26:01 Installed: openssl-devel - 0.9.8b-10.el5.i386 Oct 03 23:26:01 Installed: mysql-devel - 5.0.58-jason.2.i386 Oct 03 23:37:50 Erased: perl-DBD-MySQL Oct 03 23:37:50 Erased: mysql-server Oct 03 23:37:50 Erased: mysql Oct 03 23:37:50 Erased: mysql-devel Oct 03 23:40:26 Installed: mysql - 5.0.45-7.el5.i386 Oct 03 23:40:26 Installed: perl-DBD-MySQL - 3.0007-1.fc6.i386 Oct 03 23:40:27 Installed: mysql-devel - 5.0.45-7.el5.i386 Oct 03 23:40:27 Installed: mysql-server - 5.0.45-7.el5.i386 Oct 03 23:42:25 Erased: mysql-devel Oct 03 23:42:25 Erased: perl-DBD-MySQL Oct 03 23:42:25 Erased: mysql-server Oct 03 23:42:25 Erased: mysql Oct 03 23:51:31 Installed: yum-priorities - 1.1.10-9.el5.centos.noarch Oct 04 00:21:56 Installed: mysql - 5.0.45-7.el5.i386 Oct 04 00:21:57 Installed: perl-DBD-MySQL - 3.0007-1.fc6.i386 Oct 04 00:21:57 Installed: mysql-server - 5.0.45-7.el5.i386 Oct 04 01:57:17 Erased: mysql-server Oct 04 01:58:13 Erased: perl-DBD-MySQL Oct 04 01:58:13 Erased: mysql Oct 04 01:58:50 Installed: mysql - 5.0.45-7.el5.i386 Oct 04 01:58:50 Installed: perl-DBD-MySQL - 3.0007-1.fc6.i386 Oct 04 01:58:50 Installed: mysql-server - 5.0.45-7.el5.i386 Oct 04 02:56:26 Installed: mx - 2.0.6-2.2.2.i386 Oct 04 02:56:26 Installed: MySQL-python - 1.2.1-1.i386 Oct 04 02:57:37 Erased: MySQL-python Oct 04 02:57:37 Erased: mx Oct 04 03:12:36 Installed: php-mysql - 5.2.6-jason.1.i386 Oct 04 03:14:37 Installed: php-pgsql - 5.2.6-jason.1.i386 Oct 05 00:05:50 Installed: mx - 2.0.6-2.2.2.i386 Oct 05 00:05:50 Installed: MySQL-python - 1.2.1-1.i386 Oct 05 00:49:04 Installed: nmap - 2:4.11-1.1.i386 Oct 05 01:08:37 Erased: php-pdo Oct 05 01:08:37 Erased: php-mbstring Oct 05 01:08:37 Erased: php-mysql Oct 05 01:08:37 Erased: php-pgsql Oct 05 01:08:37 Erased: php-bcmath Oct 05 01:08:37 Erased: php-cli Oct 05 01:08:37 Erased: php-common Oct 05 01:08:37 Erased: php-gd Oct 05 01:08:37 Erased: php Oct 05 01:12:56 Installed: php-common - 5.2.6-2.el5s2.i386 Oct 05 01:12:56 Installed: php-pdo - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Updated: postgresql-libs - 8.2.9-1.el5s2.i386 Oct 05 01:12:58 Installed: php-cli - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Installed: postgresqlclient81 - 8.1.11-1.el5s2.i386 Oct 05 01:12:58 Installed: php-mysql - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Installed: php-gd - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Installed: php-mbstring - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Installed: php-bcmath - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Installed: php-pgsql - 5.2.6-2.el5s2.i386 Oct 05 01:12:58 Installed: php - 5.2.6-2.el5s2.i386