[Robert01]

porque no pruebas así:

Código Delphi [-]
  libhand := LoadLibrary('mydll.dll');
    if libhand = 0 then begin
        ShowMessage ('DLL no disponible');
    end
    else begin
      @DisplayModalForm := GetProcAddress(libhand, 'DisplayModalForm');
      if @DisplayModalForm = nil then begin
          { function no found. misspelled? }
           ShowMessage ('función no encontrada, ¿llamada erronea?');
      end
      else begin
         { call the function as usually }
        result := integer(DisplayModalForm(Pchar(AstrFormulario),VarrIdiomas, AintIdioma));
      end;
    end;
    FreeLibrary(libhand);