The org.lcsim software requires Java JDK 5.0 (also know as Java 1.5 to confuse you). You can download it from:
http://java.sun.com/j2se/1.5.0/download.jsp
You can download and install JAS3 from:
After installing JAS3 run the application and from the menu bar choose:
View, Plugin Manager
Now choose the Available Tab, and select all of the following:
- HepRep Plugin
- WIRED 4
- WIRED 4 Base Library
- org.lcsim
then click install, and then close the plugin manager.
Now you can try the getting started tutorial.