You will require Java 1.6 JRE installed on your computer to launch Index Assist.
When prompted, accept the signature on the jar file, and the application will launch.
Note that the initial download will take a moment. Thereafter, downloads should be fast.
After the first download, a desktop link should launch the application. You do not need to be online to use the application.
If you want to use a custom / already installed JRE, use this link.