cmd_write: 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/cmd_write - from package: xenomai-runtime

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

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