AClock: 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/AClock - from package: aclock.app

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

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