dvbtune: 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/dvbtune - from package: dvbtune

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

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