I want to know why . . .

On my final Multimedia project, I exported it from iMovie in three different files. The largest one was going to take five hours to upload to YouTube. The next smaller was the same amount of time. I googled iMovie to YouTube and exported it like this. But . . . every time I tried to burn it to a CD the audio messed up. I want to know why and how to prevent this from happening in the future. I really hoped we’d get more info on this; so I guess I will have to do more trial and error experimenting. My husband is usually pretty tech-savvy; but even he is stumped. If you can help, I would greatly appreciate it! Thanks! TTFN SDG