Problem with Playlists

[tw33k]

I moved my server and copied across the old files and everything is working again except my Playlists. They are visible but none of them are populated.
If I attempt to add anything to a playlist, the only option is to create a new playlist, not add to any that are already there.
I've obviously missed something when I copied the files so, does anyone have any suggestions or would it be best to delete the playlists and start from scratch?

[tw33k]

Solved! I reset the metadata for each playlist then copied the info from the old xml files into the new ones. Ran a scan and all playlists are back.