Hmmm make sure you select the correct version of your X-Fi. It sounds like its looking for a particular firmware/revision and there's at least 3-4 versions of the X-Fi from the driver download pulldown menu. Not as many as the Audigy series, but it can still be confusing. For instance, my X-Fi FPS is listed as BF00 and my Audigy 2 had a similar 4-digit firmware name.
As for the self-extracting update installations, I've never been able to get them to work properly without installing the components off the original CD first. Then the executable uninstalls them and installs the new version. Trying to install straight from the executable results in red X stop errors similar to the one Snatchface is seeing, like "unable to locate compatible device" etc.