kuser: 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/kuser - from package: kdeadmin

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

On Debian possible default full paths are:

/usr/bin/kuser - from package: kuser

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

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