My problem is mostly solved, and I wanted to post the resolution for the benefit of others who might troll the archives someday. Something about the "service iptables restart" command tripped up the modules. I re-installed the old 1.2.6a version using rpm --oldpackage -Uvh <rpm file here> and rebooted and I was back in business. I suppose that someone more familiar with kernel modules could have avoided a reboot. My next step is to re-upgrade using the RPM, but I won't enter "service iptables restart". Instead, I'll just run my standard firewall shell script.
