rumor: 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/rumor - from package: rumor

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

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