There is a "refined" problem. Really the part of source project in
BC++5.02.
Those who have D2 & D3 on computer can reproduce it.
Make a simple dll in D3  - 'DBDll.dll':
type
  TDataModule1 = class(TDataModule)
    Database1: TDatabase;
    procedure DataModule1Create(Sender: TObject);
  end;
var  DataModule1: TDataModule1;
procedure OpenMyDB; stdcall; export;
implementation
{$R *.DFM}
procedure OpenMyDB;
begin  DataModule1:= TDataModule1.Create(nil);  end;
procedure TDataModule1.DataModule1Create(Sender: TObject);
begin  Database1.Open;  end;
Make a simple project in  D2 :
type
  TForm1 = class(TForm)
    Button1, Button2: TButton;
    DBGrid1: TDBGrid;
    Database1: TDatabase;
    Table1: TTable;
    DataSource1: TDataSource;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  end;
var
  Form1: TForm1;
implementation
{$R *.DFM}
procedure OpenMyDB stdcall; external 'DBDll.dll';
procedure TForm1.Button1Click(Sender: TObject);
begin  
  Database1.Open;  //--- EXCEPTION "Capability not supported"
  Table1.Open;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
  OpenMyDB;        //If this line commented then all works normally
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
  Table1.Close; Database1.Close;
end;

Questions: 1. What is this capability and why it is not supported?
                 2. What I must do or setup in D3 to avoid this problem?