I deleted what looked to be ghost tracks, now I have no playlists?

I was recently sorting my Music and decided to put them in order of the date they were added. Some of the first files that had been added to my music were completely black, with no track information whatsoever. I tried to play the files, but all i got was a Songbird error saying that i had something like an invalid URL. Sorry, but i didn't get a screenshot. So i decided to delete the files as they seemed to be worthless. Only until I tried to open my playlists did i encounter problems
Now anytime i click on my playlists i am immediately redirected back to my Library. I think the files listed were the playlist files. I just wonder why these would be listed under my tracks as the inexperienced user might delete them?