Click/Pop noise in Nero Vision

I’m a newbie to nero vision and a newbie to this forum. I hope this is not a dumb question and I hope someone can help. I purchased nero ultra 7 and am in the middle of my first project. I am adding some background music to some soundless home videos. The problem is the sound has a lot of clicking and popping in it. The audio alone does not have this problem, only when I add it to nero with the video files. I tried burning it to the DVD to see if it still had the problem and it does. Anyone ever experience this or have any ideas what could be causing the click/pop?

Thanks for the help.