Affects both x86_64 and i386:
# yum
Traceback (most recent call last):
File "/usr/bin/yum", line 6, in ?
import yummain
ImportError: No module named yummain
It worked fine before the oct 17 update.
This is from the http://download.fedora.redhat.com/pub/fedora/linux/core/development/ repository.
-Dan