For some odd reason one version of Java will behave better on some people's systems than others. You could try stepping back to the previous version or 1.4.2
A couple of other things you could try are try deleting your LW Preferences folder whilst LW is closed; instructions here:
Fixes for Limewire Tip: Purge the Downloads Queue! Get some energy bars to give LW some more energy on those long runs. Get it fit. lol (Joke!)