tv_grab_is: 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/tv_grab_is - from package: xmltv-util

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