DIV3 decompressor

I tried to play a movie and my Realplayer said i needed a DIV3 decompressor. What is it and where do I find it? Plz help.

That’s the divx 3 codec. It can be handled by xvid (http://www.koepi.org) or divx 5 (http://www.divx.com), but not always. If either of those fail get divx 3.11 here.
http://www.divx-digest.com/software/divxcodec.html