Is your LW connected to the network (how many green connection bars do you see)? If you're connected, try this for your problem of no search results.
Problems with the search

Delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used much older versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire
This will kill all of your settings within options, you'll have to go back through afterwards & reset things.