ontv: 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/ontv - from package: ontv

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