vpbscan: 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/sbin/vpbscan - from package: libvpb0
/usr/lib/debug/usr/sbin/vpbscan - from package: libvpb-dbg

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

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