kup-server: 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 CentOS possible default full paths are:

/usr/bin/kup-server - from package: kup-server

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/kup-server - from package: kup-server

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

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