Is it the same song that causes the reboot, or does it happy on any song? Maybe there are some encoding issues with some of the songs that the music player struggles with. Possibilities also include ID3 tags with foreign characters in that the player doesnt like, or garbage in the cover art.
I use the stock music player every day and I haven't suffered a single reboot.
It *could* be hardware related, but I'd check to see if its the same song(s) that cause the reboot first.