whisper-set-aggregation-method: 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/whisper-set-aggregation-method - from package: python-whisper

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

On Debian possible default full paths are:

/usr/bin/whisper-set-aggregation-method - from package: python-whisper

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

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