next: 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/mh/next - from package: nmh

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

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