Upgrade from 6.2 to Winston Beta-2. Network was configured and working in 6.2 with "alias eth0 3c59x" in /etc/conf.modules before the upgrade. The linuxconf RPM was removed from 6.2 (my standard practice); I'm not sure if that has anything to do with this. After the upgrade and reboot, eth0 didn't load; ifconfig shows only lo0. I saw the warning about conf.modules vs. modules.conf, so I removed conf.modules. However, the new modules.conf was missing "alias eth0 3c59x" as conf.modules had. Added this line, modprobe eth0, network restart, and I was up and running. (See bug 12974 which has similar-sounding symptoms, but doesn't look like the same issue to me.)
99% chance this was an upgrade issue with the wrong modutils being installed.
Can you be more specific? Do you mean Beta-2 had a wrong modutils, and this is fixed in Beta-3? Hopefully you didn't mean that the stock RedHat 6.2 had a "wrong" modutils and can't be upgraded?