mounting failed with error 2

[Darren Pilgrim]

Reboot using the install disk, go to the Live CD.  Import the pool using 
an altroot and a cachefile:

zpool import -c /tmp/zpool.cache -o altroot=/mnt zroot

Copy /tmp/zpool.cache to /mnt/ROOT/boot/zfs/zpool.cache, then reboot 
*without* exporting the pool.