Noise once per second on Render?

[RaptrFlite]

I'm trying to render a collection of home videos that I've spliced together and put to some MP3 backing music, but once a second I get a spike of static in the mix. The video and audio sound fine aside from these cyclic spikes. I've seen this behavior before in demo software so that you can try it out, but can't use it for a finished project. My copy of Video Studio 5 SE is from my Sound Blaster Audigy order and is a full (supposedly) working version, and I've patched it with the latest patches.. Any ideas?


thanx!
Mike