A down & under mun. lol Screensavers were notorious for causing problems on macs in the past. But for OSX I'm not sure. Personally I can't afford to have mine set to auto start b/c of video processing I do. So if I leave my comp, I turn the monitor off.
Make sure you have the most recent version of Java. Restart you comp doing a Safe start & repair permissions using Disk Utility. It's generally wise to repair permissions after installing new softw. See: http://www.gnutellaforums.com/showth...6094#post96094 (permissions)

http://www.gnutellaforums.com/showth...3462#post93462

Are you attempting to use LW in the Classic environment? Not very wise to. How much ram do you have? Unfortunately, java for Mac is not very ram efficient & arguably has a bit of a memory leak.