mknbi-fdos: command not found

Have You tried accessing the binary with the full path?

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/mknbi-fdos - from package: mknbi

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