Resolution:
TIBCO BusinessWorks Collaborator (BWC) does not authenticate against LDAP. The sync option is to copy the users from LDAP->TIBCO Administrator->TIBCO InConcert. Users have to be imported into Admin Domain and then do the Workflow User Synch from Admin to IC server. For all Workflow (WF) use the users authenticated against TIBCO BusinessWorks Collaborator (BWC) Server. WF Desktop authentication is against the Administrator user repository.