Hi Mullin
If you still got the error after maintaining the org structure, chances are that it's caused by missing authorization in the RFC user. In ECC, sm59, the rfc destination pointing to CRM, the rfc user maintained there may not have adequate authorization to work with org structure. To test this, you can remotely log on to CRM, thus the logon user in CRM will be the logon user. Then you can unregister the inbound queue of the BP, debug it, to check what authority-check fails, or you can just process the inbound luw, and trace the auth checking in st01.
James