I have seen posts on various forums hinting toward it being a problem with corrupt data somewhere on the player which is being read by the database, which causes a kernel panic, bringing the player down. I know it is a little extreme, but you might want to try taking the contents of the player and copying them to your computer, deleting everything from the player (don't format). Then reboot into the original firmware and see if it still does this. If it doesn't then you know where your problem is, and you must find the source of the data corruption. This is all speculation on my part, as I have to date not seen this to be confirmed to be the cause of this problem, but it is worth trying.
If it is data corruption, and the source is your music, then you can probably get around this by re-encoding everything in a format which is not supported by the original firmware, such as ogg vorbis. The database doesn't seem to see these unsupported files and just skips past them. Good luck.