vbnc: 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/vbnc - from package: mono-vbnc

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

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