munin-asyncd: 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/sbin/munin-asyncd - from package: munin-async

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

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