xymond_alert: 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/lib/xymon/server/bin/xymond_alert - from package: xymon

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

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