Exe runs properly in debug and crash in release

Hi friends,

I am fetching a problem in which debug exe is runs properly and in release it crashed. I debug the exe in release mode and got the following things.
First I show you code:

void CPlaybackThread::_GetGraphicSurface(uint64_t        in_ui64Time,
                                         TAPIMvSurface & out_rjSurface, int iLogoIndex)
{
	HRESULT		 hr				= MV_E_FAIL;
	unsigned long	 ulCount			= 1;
	double		 dStreamTime			= 0;
	uint64_t	 ui64PlayStreamTime		= 0;
	uint64_t	 ui64MgfFrameCount		= 0;
	TAPIMvFlexReader pJMgfPlayListReader	        = NULL;
	TAPIMvPlayList	 pJMGFPlayList			= NULL;
	TAPIMvSurface    pJLastReadMgfFrame		= NULL; 
	TAPIMvAVContent  pJLastReadMgfFrameSynch        = NULL; 
	TAPIMvSurface    pJReadMgfFrame			= NULL; 

	SMvSurfaceDescription sGraphicDesc = {sizeof(SMvSurfaceDescription)};
	CPlaybackContext &playbackContext = m_pPlaybackDlg->GetPlaybackContext (m_ulCurrentReaderIndex);

	ui64PlayStreamTime	= playbackContext.GetPlayStreamTime();
	pJMGFPlayList		= playbackContext.GetMGFPlaylist(iLogoIndex);
	pJMgfPlayListReader	= playbackContext.GetMGFReader(iLogoIndex);
	ui64MgfFrameCount	= pJMGFPlayList->GetDuration();
	
   if (ui64PlayStreamTime < ui64MgfFrameCount)
   {   
		hr = pJMgfPlayListReader -> GetBuffer (&pJReadMgfFrame, &ulCount, NULL, NULL, NULL, NULL, NULL, &dStreamTime, in_ui64Time, true);
		ASSERT(SUCCEEDED(hr));
   }

   if (SUCCEEDED(hr))
   {
      if (pJLastReadMgfFrame != NULL)
      {
         hr = pJLastReadMgfFrameSynch->SignalReadCompletion();
         ASSERT(SUCCEEDED(hr));

         pJLastReadMgfFrame      = NULL;
         pJLastReadMgfFrameSynch = NULL;
      }

      if (ulCount == 1 || ulCount == 2)
      {
		  out_rjSurface = pJReadMgfFrame;

         // We have the buffer.  Release the old one
         if (pJLastReadMgfFrame != NULL)
         {
            hr = pJLastReadMgfFrameSynch->SignalReadCompletion();
            ASSERT(SUCCEEDED(hr));

            pJLastReadMgfFrame      = NULL;
            pJLastReadMgfFrameSynch = NULL;
         }

         hr = out_rjSurface->GetSurfaceDescription(&sGraphicDesc);
         ASSERT(SUCCEEDED(hr));
		 
         hr = out_rjSurface->ChangeDestinationPosition(&sPosition[iLogoIndex]);
         ASSERT(SUCCEEDED(hr));

         return;
      }
   }
}

In the above code the variable 'pJLastReadMgfFrame' is initially null, but while debugging in release without initializing this variable with any other value I got this value as not null.
From where it gets the value i am not getting. And in condition 'if (pJLastReadMgfFrame != NULL)' it enters and crashed on statement 'hr = pJLastReadMgfFrameSynch -> SignalReadCompletion ();'

Can any body help me to resolve this problem.

Tags: C++, VC++ (Visual C++ 6.0), Debugging, Release