Video Demo audio

I've been experiencing this issue as well. I posted about it about a year ago, but it doesn't seem like there's any resolution. I upgraded to a new PC and the new PC (and all others that I tested on) had the same issue with the audio. It would sound fine for the first few sections then became distorted. I was fortunate that I had my old PC that the video demos DID still work on, even the audio still worked fine. However, I just went to do a video demo yesterday from that PC and now I get that same error there too! I'm so bummed about this - this is a feature I use very frequently with Captivate. 

Sounds like a driver issue. I would check with your device manufacturer for an updated driver. You could also reach out to Adobe directly with your problem at captivatehelp@adobe.com for further assistance. This is a user forum and you will likely not get a resolution to your problem unless someone else here has had the exact same problem.