cdfbn2: 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/cdfbn2 - from package: cdftools

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

Error in other languages:
cdfbn2: bevel nie gevind nie
cdfbn2: comandă negăsită
cdfbn2: comando não encontrado
cdfbn2: commande introuvable
cdfbn2: command not found
cdfbn2: käsku ei ole
cdfbn2: không tìm thấy lệnh
cdfbn2: komanda nerasta
cdfbn2: Kommando nicht gefunden.
cdfbn2: kommandot finns inte
cdfbn2: komut yok
cdfbn2: nie znaleziono polecenia
cdfbn2: níor aimsíodh an t-ordú
cdfbn2: no se encontró la orden
cdfbn2: no s'ha trobat l'ordre
cdfbn2: opdracht niet gevonden
cdfbn2: parancs nem található
cdfbn2: perintah tidak ditemukan
cdfbn2: príkaz nenájdený
cdfbn2: příkaz nenalezen
cdfbn2: команда не найдена
cdfbn2: командата не е открита
cdfbn2: 命令找不到
cdfbn2: コマンドが見つかりません