Not sure, but the newer versions of LW have been a little buggy. Deletion of LW prefs folder sometimes fixes some issues.
Make a note of your important LW settings, then 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.)

You could also try changing your language setting to that of those you are searching for. Then typing in the songs in that language.