I get error messages like this

ERROR(545): Cannot find VENT_ID: DU+X for Ductnode: DU+X (CHID: FM_Datacenter_High_C3H6_HA)

but when I follow the error code, I see an example like this

The case set up seems to follow this example, but I still get an error. The case is not new, but I don't see where in the User's Guide where this is explained.