mount.crypt: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/sbin/mount.crypt - from package: libpam-mount

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