Runbook Designer - Access is denied ( 80070005)

Getting for some of the orchestrator users a permission error when trying to navigate the runbook designer? A gerneral error occured. The error returned was: Access is denied. ( 80070005)

First, check the following link that DCOM permissions are set: http://support.microsoft.com/kb/2779526

Second, there can be a mismatch with the SID of the user group in the runbook designer, so double check the SID is as in Active Directory, if not just re-add the group. This will trigger an update also in the Orchestrator DB with the correct SID mapping.