amgpgcrypt: 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:

/usr/sbin/amgpgcrypt - from package: amanda-server

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

On Debian possible default full paths are:

/usr/sbin/amgpgcrypt - from package: amanda-common

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

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