Wrong error code

I'm using portaudio to play a sound. I want to be able to select the output via the UI. I managed it like that :

PaError err = Pa_Initialize();
if( err != paNoError )
    return false;

qDebug() <<"Port audio succeed initialization !";

int numDevices;

numDevices = Pa_GetDeviceCount();
if( numDevices <= 0 )
{
    qDebug() << "ERROR: Pa_CountDevices returned " << numDevices;
    return false;
}

const PaDeviceInfo *deviceInfo;
bool isThereOutput = false;
int i = 0;
while(i < numDevices and !isThereOutput)
{
    deviceInfo = Pa_GetDeviceInfo( i );
    isThereOutput = (deviceInfo->maxOutputChannels > 0);
    i++;
}
if(!isThereOutput)
{
    qDebug() << "No output device";
    return false;
}

PaError errorOpening;

if(outputDevice != "")
{
    PaStreamParameters outputDeviceInfo;
    int numDevices = Pa_GetDeviceCount();

    const   PaDeviceInfo *deviceInfo;
    for(int i = 0; i<numDevices; i++ )
    {
        deviceInfo = Pa_GetDeviceInfo( i );
        if(deviceInfo->maxOutputChannels > 0 && deviceInfo->name == outputDevice)
        {
            outputDeviceInfo.device = i;
            outputDeviceInfo.channelCount = 1;
            outputDeviceInfo.sampleFormat = paInt8;
            outputDeviceInfo.suggestedLatency = deviceInfo->defaultLowOutputLatency;
        }
    }

    if(outputDeviceInfo.channelCount > 1)
    {
        errorOpening = Pa_OpenStream(&stream, NULL, &outputDeviceInfo, SAMPLE_RATE, FRAME_PER_BUFFER, paNoFlag, audioCallback, this);
    }

}

if(outputDevice == "" or errorOpening != paNoError)
{
    if(errorOpening != paNoError)
        qDebug() << "Can't open selected device ("<< outputDevice <<"), switching to the default one. Error : " << Pa_GetErrorText(errorOpening);
    errorOpening = Pa_OpenDefaultStream( &stream,
                      0,            /* no input channels */
                      1,            /* mono output */
                      paInt8,       /* 8 bits output */
                      SAMPLE_RATE,
                      FRAME_PER_BUFFER, /* frames per buffer, i.e. the number
                                              of sample frames that PortAudio will
                                              request from the callback. Many apps
                                              may want to use
                                              paFramesPerBufferUnspecified, which
                                              tells PortAudio to pick the best,
                                              possibly changing, buffer size.*/
                      audioCallback, /* this is your callback function */
                      this ); /*This is a pointer that will be passed to
                                                       your callback*/
}

if(errorOpening != paNoError)
    return false;

if(Pa_StartStream( stream ) != paNoError)
    return false;

And it fails :

Can't open selected device ( "Sortie intégr" ), switching to the default one. Error : Invalid error code (value greater than zero)

But I can't figure why OpenStream fails with a strange error code and Pa_OpenDefaultStream works like a charm.

So :

• Why does it fails ?
• Why does it throw a wrong error code ?