Playbacks stops while playing from Network Media

First of all my music is on a NAS in my home network, which is connected through a network drive. Sometimes while playing music Songbird stops at the beginning of a song and literally does nothing. I cant pause or play just go to the next or previous song. Its a little bit annoying when it suddenly is quiet in the room ;)

This never happened with other media players, no firewall is blocking and the NAS is up all the time.