Why does my Songs keep skipping to the next one by itself on my Nokia 5800 XpressMusic?

[R. S]

Every time I play a song it skips on to the next one by itself and when i look at the songs from the music library its got an exclamation mark on the songs which have been skipped. When the song skips it skips at the start before song is about to start. Can you please help me out and tell me what to do. Also not all songs skip just few of them. This happens every time I play a song. I even tried to switch off the phone and then start it again. My phone is Nokia 5800 XpressMusic. Thankz