muniwin: 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/muniwin - from package: munipack

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

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