what other version(s) of Java do you have installed on your system?

it does not make sense to have more than one JRE installed unless for developing/debugging.
you can improve limewire performance and overall java performance by upgrading to version 1.4.0 which is faster than 1.3.1. (some java programs had compatibility issues with 1.4.0- check for updates of those.)

but you should not be using any java version below 1.3.1!

mahalo