zcrypt: 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 Debian possible default full paths are:

/usr/bin/zcrypt - from package: barnowl

You may install the required package with command apt-get install {package}

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