xmotd: 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/xmotd - from package: xmotd

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

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