xymonproxy: 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/xymonproxy - from package: xymon

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

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