ZPM Unable to create a ZPM subscription for RedHat 6

When attempting to set up a RedHat Subscription in ZCC, at Step 3 of the configuration wizard, when attempting to add in the SystemID file, the following ZCC error was produced:

The wizard cannot continue for the following reason(s)" There is no system id file found in the path you have entered. Enter correct systemid path (absolute path).

Workaround: Currently RHN Subscription Management is not supported with ZCM ZPM. Using the RHN Classic method will allow the subscription set up using the SystemID file.

It was discovered that the RHEL 6 servers were initially registered with RHN Classic, then moved to Subscription Management. After the move, the SystemID files remained on some of the Subscription Management servers.

The SystemID file only applies to systems registered with RHN Classic. There is no SystemID file for systems registered with Subscription Management as it's certificate based.

It was found that the RHEL 5 servers that were under RHN Classic, were able to be successfully registered using those credentials with ZPM.

Error from ZCC.log:

29 Aug 2013 08:52:06 ============== Exception (begin) ===========================
29 Aug 2013 08:52:06 Exception occured
com.novell.zenworks.subscriptionSession.conf.SubscriptionSessionConfException: com.novell.zenworks.subscriptionSession.server.SubscriptionServerException: XML-RPC fault -9 occurred while communicating with the remote server. Message from server:
Error Message:
    Please run rhn_register (or up2date                     --register on Red Hat Enterprise Linux 3 or later)
                    as root on this client
Error Class Code: 9
Error Class Info: Invalid System Credentials.
Explanation:
     An error has occurred while processing your request. If this problem
     persists please enter a bug report at bugzilla.redhat.com.
     If you choose to submit the bug report, please be sure to include
     details of what you were trying to do when this error occurred and
     details on how to reproduce this problem.
 at com.novell.zenworks.subscriptionSession.ReplicateSubscriptionImpl.Connect(ReplicateSubscriptionImpl.java:509)
 at com.novell.zenworks.admin.pages.subscriptions.wizards.newSubscription.RemoteServerPage.validateRHNSystemID(RemoteServerPage.java:590)
...........more

Additional information about error from RedHat's support page:

https://access.redhat.com/site/solutions/5107