rubber: 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/rubber - from package: rubber

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

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