How old is the equipment model ? I know at one point in timeI think round about the 2010 release there were changes made in the XDATA structure of equipment to allow for new functionality.

The other option could a units mismatch in the config file. I have had this before with nozzles before were a model was done in metric/inch units and then opened with the config set to metric/metric. The nozzles are then not editable.