Problems activating an Evaluation Subscription

Hi,

I recently obtained an evaluation subscription for "30 Day Self-Supported Red Hat Enterprise Linux Developer Workstation Evaluation".

It's listed within my account portal.

I've installed 6.3 on my machine and successfully registered the machine. That machine appears correctly under Units > Systems with "0 Subscriptions Attached".

When I use the subscription manager (GUI or CLI) to try and attach the subscription to that machine, I get the error, "Error getting subscription. Too many content sets for certificate ... a newer client may be available to address this problem." It refers me to 

https://access.redhat.com/knowledge/solutions/129003

I'm not quite sure how to interpret the content of that article. Is it suggesting I create a patch DVD to get an updated client?

Help would be greatly appreciated on this - I've spent several hours trying to understand the resolution.

Thanks,
Dave