otl2docbook: 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

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/otl2docbook - from package: vim-vimoutliner

You may install the required package with command apt-get install {package}
Error in other languages:
otl2docbook: bevel nie gevind nie
otl2docbook: comandă negăsită
otl2docbook: comando não encontrado
otl2docbook: commande introuvable
otl2docbook: command not found
otl2docbook: käsku ei ole
otl2docbook: không tìm thấy lệnh
otl2docbook: komanda nerasta
otl2docbook: Kommando nicht gefunden.
otl2docbook: kommandot finns inte
otl2docbook: komut yok
otl2docbook: nie znaleziono polecenia
otl2docbook: níor aimsíodh an t-ordú
otl2docbook: no se encontró la orden
otl2docbook: no s'ha trobat l'ordre
otl2docbook: opdracht niet gevonden
otl2docbook: parancs nem található
otl2docbook: perintah tidak ditemukan
otl2docbook: príkaz nenájdený
otl2docbook: příkaz nenalezen
otl2docbook: команда не найдена
otl2docbook: командата не е открита
otl2docbook: 命令找不到
otl2docbook: コマンドが見つかりません