screen capture is one option, since it will capture to avi, otherwise, just look for freeware on this or other sites such as freeware.com or videohelp.com for a tool
If the mp4 contains MPEG-4 part 2 video and mp3 audio then you can simply remux to avi or .divx. Even if the mp4 contains AVC and aac audio, you can still remux to avi. Can't see much point though.