convertdvbdb: 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/convertdvbdb - from package: dvbstreamer

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

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