need help on how to convert mp4 to avi in winavi 7.1 version

There is no install on mp4 in winavi 7.1 version although the quicktime codec is already install but there is no way I could convert mp4 to avi and I want to convert my mp4 file to avi or divx file.

Have you installed the codec for avi? like divx or xvid?
And why not use v7.7 of winavi?