openmx: 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/openmx - from package: openmx

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