ptaskset: 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/ptaskset - from package: python-schedutils

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

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