stone: 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/stone - from package: stone

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

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