Создание графического редактора, ошибка "Unresolved external"

//---------------------------------------------------------------------------
void __fastcall TForm1::Image3MouseDown(TObject* Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
 if ((Sender == Image4)||(SBColor->Down))
    {
     if (Button == mbLeft)
      {
        Image1->Canvas->Brush->Color = ((TImage*)Sender)->Canvas->Pixels[X][Y];
        Image1->Canvas->FillRect(Rect(0,0,Image1->Width,Image1->Height));
      }
      else
      {
        Image2->Canvas->Brush->Color = ((TImage*)Sender)->Canvas->Pixels[X][Y];
        Image2->Canvas->FillRect(Rect(0,0,Image2->Width,Image2->Height));
      }
    }
  else if (SBBrush->Down)
      {
        if(Button == mbLeft)
          Image3->Canvas->Brush->Color=Image1->Canvas->Brush->Color;
        else Image3->Canvas->Brush->Color=Image2->Canvas->Brush->Color;
             Image3->Canvas->FloodFill(X,Y,
                                      Image3->Canvas->Pixels[X][Y],fsSurface);
      }
}
//---------------------------------------------------------------------------