Try updating your Java:
Java SE Downloads
Download the JRE offline installer & remove any other Java versions (via Add/Remove Programs) before installing this one.
Next, delete LW's preferences folder when LW's properly
closed. See point 3 here & also point 2 if you've used older versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire
This will change all of your settings within options, you'll have to go back through afterwards & reset things. If you're not sure of your settings, go through LW's tools > options & write them all down, so that you can reset things later.
If that doesn't work, try reinstalling LW. See LOTR's advice here:
http://www.gnutellaforums.com/320995-post377.html
If you want to keep using that older version, there's a 4.16.6 that I've hosted here:
LW basic 4.16.6.exe