mp2bug: 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/mp2bug - from package: mod_perl

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

Error in other languages:
mp2bug: bevel nie gevind nie
mp2bug: comandă negăsită
mp2bug: comando não encontrado
mp2bug: commande introuvable
mp2bug: command not found
mp2bug: käsku ei ole
mp2bug: không tìm thấy lệnh
mp2bug: komanda nerasta
mp2bug: Kommando nicht gefunden.
mp2bug: kommandot finns inte
mp2bug: komut yok
mp2bug: nie znaleziono polecenia
mp2bug: níor aimsíodh an t-ordú
mp2bug: no se encontró la orden
mp2bug: no s'ha trobat l'ordre
mp2bug: opdracht niet gevonden
mp2bug: parancs nem található
mp2bug: perintah tidak ditemukan
mp2bug: príkaz nenájdený
mp2bug: příkaz nenalezen
mp2bug: команда не найдена
mp2bug: командата не е открита
mp2bug: 命令找不到
mp2bug: コマンドが見つかりません