grub-crypt: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/sbin/grub-crypt - from package: grub

You may install the required package with command yum install {package}

Error in other languages:
grub-crypt: bevel nie gevind nie
grub-crypt: comandă negăsită
grub-crypt: comando não encontrado
grub-crypt: commande introuvable
grub-crypt: command not found
grub-crypt: käsku ei ole
grub-crypt: không tìm thấy lệnh
grub-crypt: komanda nerasta
grub-crypt: Kommando nicht gefunden.
grub-crypt: kommandot finns inte
grub-crypt: komut yok
grub-crypt: nie znaleziono polecenia
grub-crypt: níor aimsíodh an t-ordú
grub-crypt: no se encontró la orden
grub-crypt: no s'ha trobat l'ordre
grub-crypt: opdracht niet gevonden
grub-crypt: parancs nem található
grub-crypt: perintah tidak ditemukan
grub-crypt: príkaz nenájdený
grub-crypt: příkaz nenalezen
grub-crypt: команда не найдена
grub-crypt: командата не е открита
grub-crypt: 命令找不到
grub-crypt: コマンドが見つかりません