apoo: 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/apoo - from package: apoo

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

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