obm-dir: 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/obm-dir - from package: obmenu

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