xload: 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/xload - from package: xorg-x11-apps

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

On Debian possible default full paths are:

/usr/bin/xload - from package: x11-apps

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

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