When running the command "rhn_register" the command errors with "Installation Number Invalid", how does the system get registered?
If error occurs during Installation simply click the "Skip" button and follow directions below. This error message occurs because there may not be internet connectivity during installation process.
If error occurs after Installation has been completed the following command can be run in a terminal window as root:
# rhnreg_ks --username=<your RHN ID> --password=<your RHN password>
Directions may also be viewed here: https://access.redhat.com/kb/docs/DOC-2395