Is your LW connected (how many green connection bars do you see)?

If your connection is ok, try this: Problems with the search

If that doesn't help, 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 kill 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 there's a connection problem, please give us your details.
System details - help us to help you (click here)


If you're new to LW, you should probably read through the FAQ & User Guide
LimeWire FAQ and User Guide