Someone else had same issue. Might need to re-check both your iTunes & LW settings to be sure they are set to do this. Could possibly even disable then re-enable the options to get it back to how it was. Unwanted wipeout of Limewire library due to iTunes update... Help!

Remember using LW 5 you can have song files auto-added to iTunes (copied to the iTunes music folder). How to transfer music to my iPod (& iTunes) {click on link}