mount: / not mounted or bad option

I'm running a custom Raspbmc build on my raspberry pi. On startup, I always see the message mount: / not mounted or bad option The filesystem is still mounted, but still want to know what's causing the trouble. my /etc/fstab looks like this: proc /proc proc defaults,noatime,nodiratime 0 0 devpts /dev/pts devpts rw,nosuid,noatime,nodiratime,gid=5,mode=620 0 0 /dev/mmcblk0p1 /boot vfat ro,noatime,nosuid,nodiratime 0 0 UUID=7e790ee3-660b-46ab-8378-d8ea91730162 / ext4 defaults,data=writeback,nobh,nodiratime,noatime 0 0 tmpfs /home/pi/.xbmc/temp tmpfs rw,size=5M,nosuid,noexec,nodev,noatime,nodiratime,gid=1000,uid=1000 0 0 /tmp /var/tmp none rw,noexec,nosuid,nodev,bind 0 0