Nokia :: 5230 / Music Player Unable To Detect Files

I got my 5230 updated to 20.0.005 last time, and actually it's a good update. The performance is better than before, but I encountered a problem that really annoying me.I love listening to music. It's everything for me. But now the music player can't detect new music files, even it's imported from a blue tooth connection. After I save it from the inbox, sometimes it said "General : System Error". The files is inside the memory card, but can't be detected by the music player although I refresh the music library. The same thing happened when I import some music files from the computer using Nokia PC Suite. In the library, there is the artist's name or the album's name, but after I clicked it, there isn't any music files inside. What happened actually with the music player?About the memory card, I got it from the phone package. It's 2 GB, and still has approx. 130 MB free. Is it the memory card or the update?