Ok, the installation is easier now.
After you run the exe it shows you the codec version. Click "I accept" and it will unzip the codec in a temp folder. Now it asks you "do you wish to install DivX?", so say yes and wait \'til the process message disappears( 15-20 sec). The codec will be installed.
If it still doesn\'t give you any picture, check if you configured your MPlayer to view .avi formats( open Mplayer and click View>Options>Formats and see if Video/Avi archives is selected). Then open the videos.
PS: sorry for the slow server; the site is new and they\'re still having some speed problems, but at least the videos are awesome.