dvblastctl: 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/dvblastctl - from package: dvblast

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