unmo3: 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/unmo3 - from package: unmo3

You may install the required package with command apt-get install {package}
Error in other languages:
unmo3: bevel nie gevind nie
unmo3: comandă negăsită
unmo3: comando não encontrado
unmo3: commande introuvable
unmo3: command not found
unmo3: käsku ei ole
unmo3: không tìm thấy lệnh
unmo3: komanda nerasta
unmo3: Kommando nicht gefunden.
unmo3: kommandot finns inte
unmo3: komut yok
unmo3: nie znaleziono polecenia
unmo3: níor aimsíodh an t-ordú
unmo3: no se encontró la orden
unmo3: no s'ha trobat l'ordre
unmo3: opdracht niet gevonden
unmo3: parancs nem található
unmo3: perintah tidak ditemukan
unmo3: príkaz nenájdený
unmo3: příkaz nenalezen
unmo3: команда не найдена
unmo3: командата не е открита
unmo3: 命令找不到
unmo3: コマンドが見つかりません