Many people seem to delight in taking the time to crowbar things that do not work properly into AVI files (h.264, subs, VBR audio, VFR video....).
A few things though,
What does GSpot say about your video (if you can post the log here please do so):
http://www.headbands.com/gspot/
Does it play back properly in media player (more accurately does graphedit render it properly, if you are unaware of graphedit do not worry)
If you open it in virtual dub do any errors appear?
You may also want to try selecting direct stream copy and source audio and saving as a new AVI file.
If none of that works and you can post a link (i.e. it is legal for you to do so and you are happy to do so) one of us could take a look at the file.