Unable to figure out the reason of not calling waveoutopen()

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VC++

I have MFC application which takes the input(text) from another application convert the it to speech(using WaveoutOpen),My mfc application will get continuoes inputs from the second application not the problem is my MFC application closes abromally and doesnot voice out. it happens randomly out of 10 inputs it will closes some 2 times approx.couldn't figure out the problem.Some times application doesnt even call waveoutopen and closes.any kind of suggestion is appreciated.

What I have tried:

InitializeSpeak(hTtsInst, pInText, hEditBox, &stSpeak);
	
    /*-- Open audio channel. --*/
    pcmWaveFormat.wf.wFormatTag      = WAVE_FORMAT_PCM;
    pcmWaveFormat.wf.nChannels       = 1;
    pcmWaveFormat.wf.nBlockAlign     = 2;
    pcmWaveFormat.wf.nSamplesPerSec  = freq;
    pcmWaveFormat.wf.nAvgBytesPerSec = pcmWaveFormat.wf.nSamplesPerSec * pcmWaveFormat.wf.nBlockAlign;
    pcmWaveFormat.wBitsPerSample     = pcmWaveFormat.wf.nBlockAlign * 8;
	
#ifdef USE_SEMAPHORES
	
	
    char a[20];
    nMmRes = waveOutOpen (&(stSpeak.hWaveOut), WAVE_MAPPER,  (LPWAVEFORMATEX)                  &pcmWaveFormat,(DWORD) SpeakCallBack, (DWORD)(stSpeak.hPcmSema4), CALLBACK_FUNCTION|WAVE_ALLOWSYNC);
itoa(nMmRes,a,20);
LOG(a);///TO log the return value of waveOutOpen
		
#else	
    nMmRes = waveOutOpen (&(stSpeak.hWaveOut), WAVE_MAPPER,  (LPWAVEFORMATEX) &pcmWaveFormat,0, 0, CALLBACK_NULL);
	
#endif
	
    if (MMSYSERR_NOERROR != nMmRes) 
{       waveOutGetErrorText (nMmRes, szErr, sizeof (szErr) / sizeof (TCHAR));
		// Notify(hwnd, szErr);
        return NUAN_E_NOK;
    }