dvbdate: 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/dvbdate - from package: dvb-apps

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

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