ding: 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/ding - from package: ding

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

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