Ohh...I stumbled into something similar I think a time back. Managed to delet an equipment but one of the nozzles where still in the DS. In my case I think it had something to do with the equipment werent put on a Unit and later moved to a unit.
I guess the users have already tried "Check In All"/ "free all"?
If so I think u have to login to PW-administrator and free the components....this could make some of the nozzle become corrupt thou since some of the nozzles/datums werent checked in correctly.