amsstop: 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/amsstop - from package: ion

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

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