LimeWire doesn't need Java 1.3.1. You will need to install Java2 1.4.0_1 (the latest release candidate) or Java2 1.4.0 without LimeWire running - and preferably install LimeWire after installing the new Java.

LimeWire 2.5.5 is pretty good at not losing the download list - but it can do so if you open and close it too rapidly (sometimes).

The main file that stores download information is download.dat in the incomplete folder. You may be able to back this up - but LimeWire may get distinctly upset when the contents of the incomplete folder don't match the download.dat file - your risk.

Mark