pof4: 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/pof4 - from package: mh-book

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

Error in other languages:
pof4: bevel nie gevind nie
pof4: comandă negăsită
pof4: comando não encontrado
pof4: commande introuvable
pof4: command not found
pof4: käsku ei ole
pof4: không tìm thấy lệnh
pof4: komanda nerasta
pof4: Kommando nicht gefunden.
pof4: kommandot finns inte
pof4: komut yok
pof4: nie znaleziono polecenia
pof4: níor aimsíodh an t-ordú
pof4: no se encontró la orden
pof4: no s'ha trobat l'ordre
pof4: opdracht niet gevonden
pof4: parancs nem található
pof4: perintah tidak ditemukan
pof4: príkaz nenájdený
pof4: příkaz nenalezen
pof4: команда не найдена
pof4: командата не е открита
pof4: 命令找不到
pof4: コマンドが見つかりません