Fail to build the project

[Yahasana]

I'm struggling to build the pgDiagramDesigner.bpg but fail.
[Fatal Error] DiagramDesigner.dpr(1): Unit not found: 'System.pas' or binary equivalents (DCU,DPU)

[meesoft]

It looks like a Delphi installation or setup issue, as System is built into Delphi and should always exists. I think it should be in this path