Jim,
Upload a short piece of the original footage somewhere.
Although this may seem baffling, it's not that uncommon.
Digital camera makers don't necessarily play by a set of rules.

That's a great idea, except I cannot make any of the source material public. Big corporation, etc. I did ask the producer to check and see if these files are native from the camera. Considering the resolution is pretty high, I'm wondering why the camera would save things as mp4/aac. I'm hoping whoever submitted the files dumped them into a computer, ran them through something to put it on a flash drive, and that software crunched the files. Hopefully, there are better versions of these clips available. In the meantime, I'm going to continue to pursue a way of extracting the audio from the video and converting it to something Vegas likes. I'm also trying to rebuild a system I had worked up on my old XP machine where I could play stuff within the computer and record it simultaneously to Sound Forge. If I can remember how I routed it within the computer, I should be able to do the same thing with my W7 machine. It's machine noise, not a symphony, so audio perfection isn't completely mandatory. After all it was recorded with a camera's built in mic. :)

It's getting very difficult to follow this discussion, but If I understand correctly you're now in a position where you can get the video to show up in Vegas (32-bit at least) but you still can't get the audio ro appear in Vegas?

In that case, it should be fairly easy to get over that hurdle - simply save the audio separately from AviDeMux as a .wav and use that .wav in Vegas instead of the audio in the .avi.

To do this
1. Open AviDeMux
2. Drag/Drop your .avi into AviDeMux
3. Under "Audio" select "PCM"
4. On the Menu bar choose Audio|Save (or press CTR+ALT+S)
5. Give the audio file a suitable name (you'll need to explicitly add the ".wav" at the end), navigate to a suitable place to save it, and finally click on "Save"

Now you should be able to open this .wav file in Vegas and sync it up with the video from the .avi.

Best of luck

Mark

Thanks Mark, that helped me figure out how to make the program work. It did, in fact, separate out the soundtrack and let me assemble it with the video on the timeline. Of course I still have a thing to two to work around. It seemed like the video wasn't playing on the timeline. Even at draft, the playback didn't look good at all. I was starting to wonder if Vegas was even able to play the file. Did a quick render. The video was playing much more normally, so that is going to be okay. Unfortunately, after rendering, the audio was flat line again. Apparently, I'll have to experiment and figure out which formats Vegas will output properly with this comination of files.