busybox.petitboot: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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:

/sbin/busybox.petitboot - from package: busybox-petitboot

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