[QUOTE=tooki]I doubt this will help, but since it has no negative side effects*, it can't hurt to try: open iTunes, select the Library, and then Select All the songs in the library. Then choose Advanced -> Convert ID3 Tags... and choose version 2.4. Press OK, and iTunes will write out all the ID3 data to the tracks, including data that had hitherto lived only in the iTunes library file.
tooki
Thanks a lot. I did not do what you propose, but it reminded me that the library file might simply be missing the songs. I actually just installed the machine, and just copied over some files etc. Everything was working ok in iTunes (playlists, etc.), but somehow (part of) the library was not ok. So I just dropped my folder with the mp3 files in iTunes, and now everything is ok (although nothing visibly changed).
Again: thanks. I really like the screensaver :-)