Openplant Isometrics Manager - Master Unit Error

How do I resolve the following issue highlighted below.

[8/3/2018 5:12:49 PM]    Loading 1 i-models
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                        Starting i-model engine
                       
i-model master unit 'Feet' is not matching with 'MILLIMETERS', specified as PROJ_MASTER_UNIT in OP_Modeler_V8i project pcf. You might have selected wrong workspace project or i-model.

[8/3/2018 5:12:51 PM]    Loaded 0 out of 1 i-models
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Openplant Modeler v8i (SS5) - 08.11.09.568

Openplant Isometrics Manager (SS5) - 08.11.09.574

Thank you.