You'll need an initrd to start LVM up so that you can mount your boot partition.
In the meantime, use your installation DVD/CD to boot up. Don't attempt to mount your partitions, but accept the huge kernel, the default keyboard, and log in as root. Once you've done that, enter the following commands...
mkdir -p /var/lock/lvm
/sbin/vgchange -ay --ignorelockingfailure
/sbin/udevadm settle --timeout=10
mount /dev/lvfelix/root /mnt/fix
mount -R /proc /mnt/fix/proc
mount -R /sys /mnt/fix/sys
mount -R /dev /mnt/fix/dev
...and at this point, you should be able to run the /usr/share/mkinitrd/mkinitrd_command_generator.sh script to create your initrd. Ensure that /etc/lilo.conf has the correct stanza in it and re-run lilo. Reboot.
You might want to point /boot/vmlinuz to the generic kernel, too, before you re-run lilo and reboot.