It's a java problem. But you don't want to reinstall it. Did you originally install both LW & Java using the "Offline" version? If not, that's the way to go (remove all other versions of Java 1st.) Also deleting your LW preferences, instructions here: Point #2 & 3 in Fixes for Limewire (sample image included.)

Also make sure your firewalls are properly configured to allow LW & modem/router has UPnP enabled: Connection problems? Check here first! (click on link)