I did "yum -y update" and got following error when successfuly downloaded all the packages,
Transaction Summary
=====================================
Install 50 Package(s)
Update 797 Package(s)
Remove 0 Package(s)
Total size: 1.7 G
Downloading Packages:
Running rpm_check_debug
ERROR with rpm_check_debug vs depsolve:
rpmlib(PayloadIsXz) is needed by xine-lib-extras-freeworld-1.1.16.3-2.fc12.i686
rpmlib(PayloadIsXz) is needed by opencore-amr-0.1.2-1.fc12.i686
rpmlib(PayloadIsXz) is needed by ffmpeg-libs-0.5-3.svn20091007.fc12.i686
rpmlib(PayloadIsXz) is needed by x264-libs-0.0.0-0.25.20091007git496d79d.fc12.i686
rpmlib(PayloadIsXz) is needed by libmpeg2-0.5.1-8.fc12.i686
rpmlib(PayloadIsXz) is needed by k3b-extras-freeworld-1:1.0.5-7.fc12.i686
rpmlib(PayloadIsXz) is needed by gstreamer-ffmpeg-0.10.8-2.fc12.i686
rpmlib(PayloadIsXz) is needed by gstreamer-plugins-ugly-0.10.12-3.fc12.i686
Complete!
(1, [u'Please report this error in http://yum.baseurl.org/report'])