Limewire Pro 4.9.37
Blue bars = Turbo Charged, steady connection
I can do other searches such as for music and I get search results, but
when I choose to do a document search, there are no search results.

It's the weirdest thing, Limewire was working fine last week, I found all sorts of books. I havent changed a thing on my computer, no new software, no setting changes, nothing - everything works except Limewire when I'm searching documents.

Hope this helps.

Try deleting 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 change all of your settings within LW's options, you'll have to go back through afterwards & reset things to the way you like them.
Vista users: LimeWire Pref Folder in Vista

You could also try disabling ultrapeer capabilities (tools > options > speed > tick 'disable ultrapeer capabilities > apply > ok) & see if that makes any difference.