Retrieving list of all available packages... There was a fatal error communicating with the server. The message was: Invalid Architecture and OS release combination version 2.1.7
This error typically indicates that you are trying to retrieve updates for a os release that isnt currently supported. check the output of: rpm -q redhat-release and the contents of /etc/sysconfig/rhn/system_id, to see which os release it claims. up2date determines what OS release you are based on the contents of /etc/sysconfig/rhn/system_id, which is created based on amongst other things, the version of the "redhat-release" package.
Please provide us with the requested information so we may assist you.
Assigned QA to jturner
closed due to lack of additional feedback. Assuming 6.2EE, which has been added.