xymonping: 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/xymonping - from package: xymon

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

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