the is a little more information needed than that. You should import the pool from another system/stick/cd and do a 'zfs list -r pool' on it and check the mountpoints. It seems they are not propely set.
There are basically two ways to get it to work:
Set the mountpoint using zfs:
$ zfs set mountpoint=/ your/ROOT/dataset
Set your /bin, /var and so on dirs via inheritance or manually. When you are done you may check if they are set properly by using the 'zfs list -r pool' or 'zfs get mountpoint pool' commands.
Or use the traditional fstab and the zfs legacy option:
$ zfs set mountpoint=legacy your/ROOT/dataset
$ cat /etc/fstab
rpool/ROOT/void / zfs rw,relatime,xattr,noacl 0 0
rpool/ROOT/void/var /var zfs rw,relatime,xattr,noacl 0 0
rpool/ROOT/void/boot /boot zfs rw,relatime,xattr,noacl 0 0
/dev/mapper/swap_crypt swap swap defaults 0 0
tmpfs /tmp tmpfs defaults,nosuid,nodev 0 0
In this case you have to make sure that your fstab is included in your initrd.