Try removing your current version of Java (add/remove programs) & reinstall JRE using the offline installer, see point 1 below
Fixes for LimeWire
Delete the LW preferences folder (make sure LW's properly closed first), see points 2 & 3 above.
If that doesn't help, try reinstalling LW using the offline installer
http://www.limewire.com/english/content/download.shtml