Sorry I missed your mention of the screensaver in your 1st post.

Well I could suggest a few things which might fix it. But I don't know whether any particular one will necessarily fix it.
1. Change LW's compatibility mode to win 2k (see point 4 in this link: Fixes for Limewire
2. Update your Java to 1.5
3. Reduce your shares slightly but only if you share over 1,000 files.
4. Tip: Purge the Downloads Queue!

You might not be keen on the last 2 suggestions. Try the 1st one or 2 suggestions anyway.