youtube finally seems to have started cracking down on downloader programs a couple days ago so if that stops working, there's a way around it. If you have a somewhat older computer and especially not an intel based system, your sound adapter can probably internally loop itself. I'm not familiar with your particular software but somewhere there should be an option to set the default recording device or channel. Choose "stereo mixer" and set the volume pretty low. Then it will record basically anything that's coming out of your audio output to the speakers or headphones. So play the youtube video and don't make any other sounds on your computer and it'll record it in realtime.