What happens when you try to download?
Do you see the file appear at the bottom of the search results section? Does it say 'stalled'? If the file's stalled, either try clicking 'try again' or else start a new search for the file.
If nothing's showing at all below search results, try this:
http://www.gnutellaforums.com/downlo...tml#post338001
If you want to use LW 4 again, there's a page to download old installers:
Lime Wire » Download Out-Of-Date Installers
If you're using Pro, your personal download page has a link to 4.18.8 on the left hand side - 'Get LimeWire Classic'.