Hey Nicholas,
That AAA-SYS-0001 is an IBM Cognos error, but OCI uses its own authentication plugin for IBM Cognos, not the native stuff, so the google results for AAA-SYS-0001 may not be germane.
It would be interesting to know if you are using LDAP in conjuction with your OCI DWH configuration though.
Do you have a support case open on this? I am not aware of this being a known issue
Matt