iTunes playlists suddenly disappeared

Hi

after working well for at least a year (even with Lion 10.7.4) all my playlists suddenly disappeared. I followed advise (from OSX Daily website) and quit iTunes (10.6.1), moved 'iTunes Music Library.xml' and 'iTunes Library.itl' folders to desktop and re-imported and started iTunes again, whereupoon I expected to see my playlists restored, BUT instead this re-import process seemed to automate a completly new duplication of all the mp3 s into the Media folder, as if by some default.

To be clear, I keep all my mp3's in Music / iTunes Music. I think iTunes really wants me to keep my mp3 files in Music / iTunes / iTunes Media / Music as this directory recongnises games and other forms of revenue for Apple but I elected to keep my files seperately and iTunes does say it allows me to do this by duly selecting the path in Preferences / Advanced, and un-check the 'keep Media folder organised' radio button...... and this has worked pretty well ....until two days ago. So what has happened to disturb the peace?

Grateful for any advice here.