Currently the EPEL snippet won't work due to this link being used:

http://download.fedoraproject.org/pub/epel/$major/$arch/epel-release-$os.noarch.rpm

As per this mailing list post:

http://lists.fedoraproject.org/pipermail/users/2012-February/414558.html

download.fedoraproject.org redirects elsewhere, which breaks the rpm command. If you change the subdomain to 'dl', like so:

http://dl.fedoraproject.org/pub/epel/$major/$arch/epel-release-$os.noarch.rpm

It works.