My suggestions are summarized here: If LW Will Not Connect (click on the blue link). I believe replacing the gnutella.net file, and purging the incomplete files are the two more important ones in your cases.

If problems searching, sometimes that happens to us all. There are odd days when searches are extremely poor giving little or anything. I don't know the entire reasons, but one reason might be because you are connected to dud or spam ultrapeers. Replacing the longest connected ultrapeers one by one at a time 'might' improve things, but can play havoc with your connection after each one is removed. So if that is done, wait several mins after each one, see if searches improve before replacing any more.

Here's two other things to try: (a) Problems with the search, __ (b) Hostiles List