rtf2brl: 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/rtf2brl - from package: liblouisxml-bin

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

Error in other languages:
rtf2brl: bevel nie gevind nie
rtf2brl: comandă negăsită
rtf2brl: comando não encontrado
rtf2brl: commande introuvable
rtf2brl: command not found
rtf2brl: käsku ei ole
rtf2brl: không tìm thấy lệnh
rtf2brl: komanda nerasta
rtf2brl: Kommando nicht gefunden.
rtf2brl: kommandot finns inte
rtf2brl: komut yok
rtf2brl: nie znaleziono polecenia
rtf2brl: níor aimsíodh an t-ordú
rtf2brl: no se encontró la orden
rtf2brl: no s'ha trobat l'ordre
rtf2brl: opdracht niet gevonden
rtf2brl: parancs nem található
rtf2brl: perintah tidak ditemukan
rtf2brl: príkaz nenájdený
rtf2brl: příkaz nenalezen
rtf2brl: команда не найдена
rtf2brl: командата не е открита
rtf2brl: 命令找不到
rtf2brl: コマンドが見つかりません