Mac OSX users who were using LW 5.1 .. yes the latest OSX Java update broke 5.1. Answer for time being is to use the beta 5.2.2;
LimeWire 5.2.2 (Beta) - Lime Wire which btw has some nice improvements. Download window is visible at all times, additions of filters including size filter. Ability to browse uploaders. This beta is stable. There will be a LW 5.1.4 update to fix the OSX Java issue but not sure when that will be available yet.