subtitles: 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 CentOS possible default full paths are:

/usr/bin/subtitles - from package: xawtv

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/subtitles - from package: xawtv

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

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