rhel version upgrade via up2date

I am trying to use up2date to upgrade ( a test system, with a proper 
license for RHEL ES) from RHEL 3 to RHEL 4.

When I run
up2date --upgrade-to-release=rhel-i386-es-4

I get this reply:
Error communicating with server. The message was:

Error Message:
     Your account does not have access to any channels matching 
(release='rhel-i386-es-4', arch='i686-redhat-linux')
If you have a registration number, please register with it first at 
http://www.redhat.com/apps/activate/ and then try again.
Error Class Code: 19
Error Class Info: Architecture and OS version combination is not supported.


Questions: How do I get around this error message?

Has anyone ever used up2date to update from 3 to 4 ?

What is the option '--upgrade-to-release' intended for if not this?