First, you don't want to fsck while they're mounted.

See if you can do a ``umount /dev/hda4''. Make sure the player application is stopped (that is, press `q' at the serial port) and make sure you're not cd'd into /drive0 anywhere. Then run ``fsck /dev/hda4''. If it claims that it's clean, try a ``fsck -f /dev/hda4''.

If any of those steps fail, don't go any further. Reboot and get back to us.

Then let us know what happens.