Project plays with A/V in sync in Kdenlive, rendered version goes out of sync

At the end of my rope - I've edited and effected a 1:28 minute concert film, but can't get it out of kdenlive.

The source is footage from three cameras, two encoded to DV AVI files and one in it's native mp4. Since it's a concert, I've alinged all the video clips with the best audio track and made cuts to see the angles I want. I can play without flaw in kdenlive.

The problem arises when I render. I loose audio sync, but differently depending on the export format. I realize that some effects may be caused by players rather than the encoded file, so I tested each with both GMplayer and VLC. Results:

Destination: DVD>NTSC 4:3 VOB VLC Result: Loses sync at 33:18 on a particular cut;shots from only one track are out of sync. GMPlayer result:Same

Destination: File Rendering>MPEG-2 VLC Result: Loses sync at 33:18 on a particular cut;shots from only one track are out of sync. GMPlayer result:Same

Destination: File Rendering>MPEG I-Frame Only + MP2 VLC Result: Loses sync at 33:18 on a particular cut;shots from only one track are out of sync. GMPlayer result:Same

Destination: File Rendering>AVI DV>DV NTSC 4:3 VLC Result: Audio in bursts about once every 5 seconds. GMPlayer result:No audio

Destination: File Rendering>Raw DV>DV NTSC 4:3 VLC Result: Audio Drastically out of sync from the start. GMPlayer result:No audio

Destination: Lossless/HQ>HuffYUV + PCM VLC Result: No audio. GMPlayer result:Audio Drastically out of sync from the start

My Project Profile is DV/DVD NTSC

Kdenlive Version 0.8.2.1
Using KDE Development Platform 4.8.5 (4.8.5)

Running on Ubuntu 12.04.

I will add any detail as needed; without knowing if there's a clue in what I've posted so far, I don't know how best to proceed.

Thanks in advance for any clues.