munindoc: 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/munindoc - from package: munin

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

On Debian possible default full paths are:

/usr/bin/munindoc - from package: munin-node

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

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