[CentOS] How Undo Yum Upgrade

I accidentally enabled a repo, so my automatic yum upgrade installed a 
bunch of stuff and possibly broke yum.  Is it possible to reverse this? 
  Follow is the yum log of what got installed.

Mar 04 01:34:04 Updated: libselinux.i386 1.23.10-1.99_3.el4.at
Mar 04 01:34:04 Updated: popt.i386 1.10.2-15.1_58.el4.at
Mar 04 01:34:04 Installed: libbeecrypt6.i386 4.1.2-9.2_11.el4.at
Mar 04 01:34:04 Installed: libxml2_2.i386 2.6.22-1_21.el4.at
Mar 04 01:34:04 Installed: librpm4.3.i386 4.3.3-8_41.el4.at
Mar 04 01:34:04 Updated: neon.i386 0.24.7-5.99_2.el4.at
Mar 04 01:34:05 Installed: librpm4.4.i386 4.4.2-15.1_58.el4.at
Mar 04 01:34:05 Updated: rpm.i386 4.4.2-15.1_58.el4.at
Mar 04 01:34:08 Installed: python24.i386 2.4.1-2_8.el4.at
Mar 04 01:34:08 Updated: libxml2.i386 2.6.22-1_21.el4.at
Mar 04 01:34:08 Installed: pythonabi.i386 2.3.4-1.el4.at
Mar 04 01:34:09 Updated: libxml2-python.i386 2.6.22-1_21.el4.at
Mar 04 01:34:09 Updated: rpm-python.i386 4.4.2-15.1_58.el4.at
Mar 04 01:34:09 Installed: libxml2-python24.i386 2.6.22-1_22.el4.at
Mar 04 01:34:10 Installed: rpm-python24.i386 4.4.2-11_9.el4.at
Mar 04 01:34:11 Installed: neon-devel.i386 0.24.7-5.99_2.el4.at
Mar 04 01:34:11 Updated: libselinux-devel.i386 1.23.10-1.99_3.el4.at
Mar 04 01:34:11 Installed: atrpms.noarch 67-1.at
Mar 04 01:34:12 Updated: perl-XML-LibXML.i386 1.58-4.el4.at
Mar 04 01:34:12 Installed: sqlite-devel.i386 3.2.2-1
Mar 04 01:34:13 Updated: yum.i386 2.4.2-69.el4.at
Mar 04 01:34:13 Updated: rpm-build.i386 4.4.2-15.1_58.el4.at
Mar 04 01:34:15 Updated: libxml2-devel.i386 2.6.22-1_21.el4.at
Mar 04 01:34:15 Updated: rpm-devel.i386 4.4.2-15.1_58.el4.at
Mar 04 01:34:15 Erased: rpm-libs