There are two things that come to my mind; the first thing is a standard procedure and aims at eliminating a possible preference folder corruption.
Try to delete the "LimeWire" folder in your hidden Application data folder when LW is completely closed as described in Point #2 & 3 in Fixes for Limewire (maybe look also for the old " .limewire " preference folder and delete this as well):
http://www.gnutellaforums.com/showth...threadid=36420
The second thing would point to update your Java using the JRE offline installer from here:
http://java.sun.com/j2se/1.5.0/download.jsp
Before doing so, you should uninstall all other Java versions you have presently on your system. After installing you should reboot before opening LW.
Edit:
Here is a link that talks about freezing fo LW:
http://www.gnutellaforums.com/showth...hlight=freezes 