balls: 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/balls - from package: raster3d

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

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