pof6: 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/share/doc/mh-book/examples/mh/bin/pof6 - from package: mh-book

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

Error in other languages:
pof6: bevel nie gevind nie
pof6: comandă negăsită
pof6: comando não encontrado
pof6: commande introuvable
pof6: command not found
pof6: käsku ei ole
pof6: không tìm thấy lệnh
pof6: komanda nerasta
pof6: Kommando nicht gefunden.
pof6: kommandot finns inte
pof6: komut yok
pof6: nie znaleziono polecenia
pof6: níor aimsíodh an t-ordú
pof6: no se encontró la orden
pof6: no s'ha trobat l'ordre
pof6: opdracht niet gevonden
pof6: parancs nem található
pof6: perintah tidak ditemukan
pof6: príkaz nenájdený
pof6: příkaz nenalezen
pof6: команда не найдена
pof6: командата не е открита
pof6: 命令找不到
pof6: コマンドが見つかりません