cpufreqd-set: 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/bin/cpufreqd-set - from package: cpufreqd

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

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