cpufreqnextgovernor: 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/sbin/cpufreqnextgovernor - from package: gkrellm-cpufreq

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

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