subtitleeditor: 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/subtitleeditor - from package: subtitleeditor

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

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