I have 2 (nearly) identical machines. On one of them WAU works perfectly. On the other it won't launch. When I install it says it worked, but when I run it the screen flashes up for a split second then closes. I tried watching it in the Task Manager and I see it pop up and disappear almost instantly. There is no error displayed and nothing in the Event Log. I have tried uninstalling and reinstalling it repeatedly (with both the IE install and the stand alone exe). I have reset all IE settings to their defaults and cleared the history, then reinstalled again. The system is running XP Pro and has .NET 1.2, 2.0 SP1 and 3.0 SP1 with the latest updates from microsoft for all of them.
I have also tried removing the 2.0 folder and registry key mentioned above, then reinstalling, all to no avail.