You need to redownload LW and install it. Go here.
LW Download Here
If that doesent work you need to reinstall Java. Go here to get the latest version (not beta).
https://jsecom8b.sun.com/ECom/EComAc...1765a05b9e8cc3
(Please tell me if that is not the right one, its been a while since I've done this.) That should solve your problems. Good luck.
deepblue