You do not have to download anything in order to view pages using LiveGraphics3D. However, if you want to use LiveGraphics3D on your own pages, you have to download the Java 1.1 archive presented below.
Note that LiveGraphics3D is free for non-commercial purposes but needs a license by Wolfram Research, Inc. for any commercial purposes. Please contact the author for details.
LiveGraphics3D 1.90 consists of one Java 1.1 archive:
In order to download this archive you have to click the link above with the right mouse button (and save it as source or binary) or with the left mouse button and a key modifier (usually CONTROL or SHIFT) depending on your web browser and platform. (Please consult your web browser's manual if you need more help about this point.)
The documentation explains how to install and use the file live.jar.
If the downloaded file does not work properly, you should try to download the archive again. (Make sure that you do not download a cached copy; you can check the file by trying to unzip it like any .zip archive.) If the problem remains please e-mail me and I'll send you the file as an e-mail attachment. You can also download version 1.30 from MathSource.