Cannot MOUNTPROG RPC (tcp): RPC: Remote system error - Connection refused

なぞのエラー

# mount -o tcp,rw 192.168.0.82:/tmp /cdrom
# umount /cdrom/
Cannot MOUNTPROG RPC (tcp): RPC: Remote system error - Connection refused
#

# mount -o remount,rw /cdrom
unknown nfs mount option: relatime
#