makesimple: 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/makesimple - from package: perl-Makefile-Parser

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

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