Is it an error while chrooting? What is /dev/zapper? At which step are you exactly? Trying to mount the partitions, as in this? mkdir /media/linux mount /dev/main/root /media/linux mount /dev/main/usr /media/linux/usr mount -o bind /proc /media/linux/proc mount -o bind /dev /media/linux/dev mount -o bind /sys /media/linux/sys
From the livecd or usb, in the CLI, the first command you need to type is modprobe dm-crypt, followed by cryptsetup luksOpen /dev/sda3 linux (can be sdaX, X being a number. maybe fdisk -l might tell you the name of your encrypted drive, I don't remember exactly how I've figured it out).
