vff2mnc: 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/vff2mnc - from package: minc-tools

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

Error in other languages:
vff2mnc: bevel nie gevind nie
vff2mnc: comandă negăsită
vff2mnc: comando não encontrado
vff2mnc: commande introuvable
vff2mnc: command not found
vff2mnc: käsku ei ole
vff2mnc: không tìm thấy lệnh
vff2mnc: komanda nerasta
vff2mnc: Kommando nicht gefunden.
vff2mnc: kommandot finns inte
vff2mnc: komut yok
vff2mnc: nie znaleziono polecenia
vff2mnc: níor aimsíodh an t-ordú
vff2mnc: no se encontró la orden
vff2mnc: no s'ha trobat l'ordre
vff2mnc: opdracht niet gevonden
vff2mnc: parancs nem található
vff2mnc: perintah tidak ditemukan
vff2mnc: príkaz nenájdený
vff2mnc: příkaz nenalezen
vff2mnc: команда не найдена
vff2mnc: командата не е открита
vff2mnc: 命令找不到
vff2mnc: コマンドが見つかりません