I have the same problem - Limewire ran fine for months, but now I can't launch the program. I reinstalled the latest version and it worked OK for a day. Now I get:

java.lang.NullPointerException
at com.limegroup.gnutella.bw.b(Compiled Code)
at com.limegroup.gnutella.bw.a(bw.java:513)
at com.limegroup.gnutella.bw.b(bw.java:377)
at com.limegroup.gnutella.bw.<init>(bw.java:362)
at
at com.limegroup.gnutella.gui.bo.<init>(bo.java:118)
at
at com.limegroup.gnutella.gui.Initializer.b(Initializ er.java)
at com.limegroup.gnutella.gui.Main.main(Main.java:16)
at com.zerog.lax.LAX.launch(Compiled Code)
at com.zerog.lax.LAX.main([DashoPro-V1.2-120198])
at com.apple.mrj.JManager.JMStaticMethodDispatcher.ru n(JMAWTContextImpl.java)
at java.lang.Thread.run(Thread.java)

???