need help with an error message

[mr.Timmons]

I have a PAL .avi with subtitles I am trying to convert. I think I did everything correct, but I get the following error;

"Avisynth open Failure:
AVISource: couldn't locate a decompressor for fourcc DIV3"

What does this mean and how can I fix it?
<img src="http://img290.imageshack.us/img290/9479/erroroe7.jpg">

[mr.Timmons]

OK. I was able to fix that by downloading a codec. Now I have a new error;

"AVISource: could not decompress frame 0"

now what?