You can try:
1. Super, free tool, it can convert video to all video formats including avi format.
You can download it here
http://www.erightsoft.com
2. if super doesn't works, you can try wondershare video converter platinum, I've been using it for a long time. it can convert video to other formats like super, at the same time, it is able to split/join video, much more considerate than super. Its batch conversion ability is also a highlight of this software.
You can download it here
http://www.dvd-ripper-copy.com/video-converter -platinum.html