I know SMP has something where you can add audio. I think Monkeyjam can as well, I'm not sure.
But, trying to put audio in the frame capture program means you have to figure out all the timing beforehand and compile sounds on an audio program. An easier way to add audio is to put your clips into a editing program. With that, you can add sound on a timeline with the video right there. You can insert in audio file and then move it to where you want it to be. That way, you get the audio exactly where you want it. I use Lightworks, it's a good free editor.
Not literally dead, just no longer interested in Lego or animation.