Try this reinstallation technique: http://www.gnutellaforums.com/333278-post2.html

I cannot see the version of LW. Get the offline installer: For LW 4 see under paragraph Past Releases: Get LimeWire for Your Platform - Lime Wire

For LW 5, use the link inside the first link I gave.

If still problems, check points #5 & 6 here: Fixes for Limewire (click on blue link)