inline __fastcall virtual
      TDBISAMDBDataSet(System::Classes::TComponent* AOwner) :
      TDBISAMDataSet(AOwner) { } 

You should not use this constructor to create an instance of this component directly. Instead you should create an instance of a TDBISAMTable or TDBISAMTable component, which both descend from this component and provide a published interface for use at design-time.