I'm just posting this for anyone who may have had a similar problem and couldn't figure out the root of the cause.
I'm was using PPCS5.5 on a Mac and imported a finished stereo audio track (combined dialogue, sound effects and music) onto the timeline. I realized there were a couple little sound effects I had forgotten to add originally, including the vibration of a cell phone, so I put them on a new track below the finished audio. I happened to record the sound of my iPhone vibrating with a second iPhone using the voice memo function, producing a mono .m4a file which I dropped onto the timeline.
Well, this caused all kinds of chaos when I did my final render of picture. When opeing the project a strange, unspecificed error box came up identifying a drive and directory on the system of my sound man and the picture rendered as bizarre pink and green video noise (sort of like a scrambled signal). I thought my CS and/or Mac was losing its mind. I Googled the symptoms and found mention of a problem related to "sound mapping" that can be caused by mono sound files when used in combination with audio synced via Pluraeyes.
Long story short, I converted the additional sound FX to stereo mp3s, re-imported them and no problems of any kind after that.