CentOS release 5.9 (Final) yum update found update for mod_cloudflare that was originally downloaded from Cloud Flare's website (mod_cloudflare-el5.latest.rpm) yum update was mod_cloudflare.i686 0:1.2.0-1360806316.el6 updated failed with the following ERROR with rpm_check_debug vs depsolve: rpmlib(FileDigests) is needed by mod_cloudflare-1.2.0-1360806316.el6.i686 rpmlib(PayloadIsXz) is needed by mod_cloudflare-1.2.0-1360806316.el6.i686 Complete! (1, [u'Please report this error in https://bugzilla.redhat.com/enter_bug.cgi?product=Red%20Hat%20Enterprise%20Linux%205&component=yum']) It appears this update is for Centos 6.
Doesn't see to be a yum bug. You are replacing the RHEL-5 package with a RHEL-6 one. Closing as not a bug.