audio clicking after render

[frosh]

i have a project that sounds fine in vegas, but as soon as i render it out (to avi) the audio "clicks" every second or two for the first 10-30 seconds.
there are two audio tracks: one recorded from the on-cam mic and the other recorded directly from the sound board to a laptop in audacity. i didn't record this and it is from a live event so i'm stuck with what i have. there is some clipping in the direct feed, but it doesn't sound obnoxious until after i render. other than mixing the two tracks, the only fx are eq and dynamic compression. i've also tried bypassing the compression, adding "smoothing" and dithering, rendering out the audio separately, but that doesn't seem to prevent the problem.

my system:
hp with amd 3ghz quad, win7x64, 8GB ram, vegas 8.1

i'm not inclined to think my computer is the problem, but i'm running out of ideas. has anyone experienced this before and found the cause of the problem?

 

[Lowlypawn]

I would take the audio track with the clicks and export it into a real audio editing program. Remove the clicks as best I could, EQ, normalize ETC then import it back to my project. Sync it back up and mute the original. Can’t say this will fix your problem but that's what I would try.