If the install script has a problem registering, try this:
sudo rpm -Uvh \ http://rhn.uchicago.edu/pub/rhn-org-trusted-ssl-cert-1.0-1.noarch.rpm
Then make sure your trusted sslCACert entry in
/etc/sysconfig/rhn/up2date looks like:
sslCACert=/usr/share/rhn/RHN-ORG-TRUSTED-SSL-CERT
Then run:
rhnreg_ks --activationkey=4615db501bffebd96009bb81b065c015 rhn_check
Get the proper key from the rhn website.