expirerm: 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/expirerm - from package: inn2
/usr/lib/news/bin/expirerm - from package: inn

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

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