Mmm, that's some ancient noise you're going for. xD
Anyways, I found the guide which you quoted and there was more on the directions listed.
Now you should see a list of audio codec’s. Amongst it you should find Microsoft ADPCM Audio Codec and IMA ADPCM Audio Codec (the two that I was missing) and many others. You can install what you require from here.
You need to install them one by one so select each in turn and click †˜Next’. This should re-install the codec (for the IMA ADPCM you will need your Windows XP CD, and for both you will need to restart your computer before the codec works). Repeat the procedure for each codec for which you need support
If you are asked for a .dll file with the IMA codec, use the one in the system32 folder.
Did you do verify that? :s