mod-active: 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/lib/news/bin/mod-active - from package: inn2

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

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