querychannel/stopchannel doesn't work

[White Dragon]

why when I use query channel get a crash?

for example:

int stop_last_sound() {
    int playid = openborvariant("sample_play_id");
    int channel = querychannel(playid);

    if ( channel >= 0 ) stopchannel(channel);

    return playid;
}

 

[utunnels]

The variable sample_play_id should be get right after a playsample call and should be stored elsewhere.