Div3 should play without problems with DivX codec.
Don't know what codec you downloaded as you do not mention it in your post.
You can find out what codec your video requires by using e.g. GSpot.
You can find a link to GSpot in the second item of my
Help to Help post (click on the link hereunder).
You can download latest DivX codec 5.1.1.
here.
You need not install the player which is included in this "bundle"; you can simply deselect it.
Let us know if you succeeded.