htload: 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/htload - from package: htdig

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

On Debian possible default full paths are:

/usr/bin/htload - from package: htdig

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

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