Try this technique: http://www.gnutellaforums.com/333278-post2.html

However, I would recommend LW 4.16 at present; Downgrading to LimeWire 4 from 5 & resuming incomplete downloads

You may need to delete your old LW preferences folder, however make a backup as suggested both above & here: Try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)