How to load RAPID into VC with PC SDK

Dear All

According to PC SDK user manual v2, I wrote some codes by CAPI to connect virtual controller and load RAPID module as follows:
    ... ...
    m_controller = ControllerFactory.CreateFrom(controller); 
    m_controller.Logon(UserInfo.DefaultUser);
    if(m_controller.OperatingMode != ControllerOperatingMode.Auto)
    {
     //set to Auto mode
     VirtualPanel vp = VirtualPanel.Attach(m_controller);
     vp.ChangeMode(ControllerOperatingMode.Auto);
    }
    using(Mastership master = Mastership.Request(m_controller.Rapid))
    {
     try
     {
      Task taskMain = m_controller.Rapid.GetTask("T_ROB1");
      taskMain.LoadProgramFromFile("C:\Data\System1\HOME\MainMod.pgf", RapidLoadMode.Replace);
      master.Release();
     }
     catch(GeneralException)
     {
      master.Release();
      throw;
     }
    }

The code did work until calling LoadProgramFromFile/LoadModuleFromFile, which threw InternalException. "CDataSystem1Internal" is the directory of virtual controller.
Could you please tell me the correct way to use LoadProgramFromFile/LoadModuleFromFile? Thanks.