I hope that was a typo & that you upgraded to 4.18

Are you trying to play files with LW's player?

Have you tried using another player? If not, disable LW's player (tools > options > player) & see whether another player works. Really, the LW player's bad. I'd recommend disabling it permanently & making something else your default player The link here has info about VLC player - it's free, reliable & plays most file types: http://www.gnutellaforums.com/tips-t...p3-fixers.html

But... if you really do want to use LW's player, 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 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.
Vista users: LimeWire Pref Folder in Vista