Quote from lindalasRolf,
Thanks for keeping JWU alive! The latest update does however break compatability with many of your current users such as myself because we can't install Java 6 (requires a 64-bit processor, at least for mac users). I remember we ran into this a long time ago and that time you just rolled back the java useage since you weren't actually relying on anything in java 6 per se. If you can continue to release JWU under Java 5 that would be awesome, if it is no longer possible because you need functions in Java 6, I completely understand.
This problem has been raised as an issue on the googlecode project page, and it looks like someone had a fix for it:
As i dont have a mac, or even know someone that could lend me one, i cant tell you if it works.