vct: 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/vct - from package: spark

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

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