It looks like your problem is that Winamp 2 is set to handle several different music file types (mp3, mp2, wav and wma). This means that Bemused will try to load Winamp 2 instead of Winamp 3 - and I'm guessing that you don't actually have Winamp 2 installed?
To make Bemused use Winamp 3 instead, change the default application to Winamp 2, delete all the text in the "Handles file types" text box, then change the default application back to Winamp 3.
Spent many hours fiddling with settings on my Gigabyte dongle software, finally got it working with the help of the forum and the new driver update, then discover bemused - cool app. Had the same problem, so ta 4 helping me too!
Just for ppl's info, there is a backward patch for Winamp 3 which allows you to use bemused 1.4 with it with minimal fuss. Can't remember what the file is called but doing a search on google should bring it up. (it's no longer hosted on the winamp page so don't go looking like I did for hours).
edit -- found the file name to make it easier.. it's called wa2mgr.exe
Nasher never could figure out why people called him Colgate.....