Here's a guide I made to remove the extra audio streams in a dual audio avi file. It works & very easy to do.

1. Open virtualdubmod
2. Load avi
3. Under streams, click onto streams list
4. Disable the stream that’s non English ( I use Divx player to figure this out)
5. Move the stream that you wish to use up in position.
6. Hit OK
7. Have video set to direct stream copy
8. Save avi as.....save


This will now give you a single audio stream movie, that you can watch or convert to dvd format without any problems of dual audio.